Harold, Sid, and Stinky all moon Principal Wartz, but Arnold is blamed, even though he was just an innocent bystander.

Helga's sister Olga comes home for spring break and becomes a classroom aid in Helga's class, much to Helga's chagrin.

After Sid works off a debt with loan shark Big Gino, the two become friends, but when Sid is told to give Arnold a swirlie, he has to choose between the two.

Gerald's older brother Jamie O has a sudden burst of kindness when he finds a girlfriend, but Arnold and Gerald soon find out that the girl is just using Jamie O.

After losing Eugene's birthday party invitations, Arnold feels obliged to throw him another party, but it doesn't work out.

Stinky grows a huge pumpkin to enter in a city competition.

After Bob pops his spine, Miriam runs Big Bob's Beepers. She gets in over her head and forgets about her family.

Arnold finds out that Oskar is illiterate and tries to teach him to read.

Helga wants to show Arnold that she can be as sophisticated as Lila is by taking him, Gerald, and Phoebe out to dinner with a coupon she won. She devises a plan to get out of paying when she discovers they're at the wrong restaurant.

Phoebe is promoted to the sixth grade, but realizes that her new so-called "friends" are just using her to do their homework.

A sleep-talking Helga confides into Bob's parrot about her love for Arnold. The next day, the parrot flies into Arnold's window, and it is up to Helga to get it.

Crisis strikes when Gerald's little sister, Timberly, eats a stock of chocolate turtles that he and Arnold are supposed to sell for a local scout organization.

Helga tries to separate Arnold from Lila while at the annual Cheese Fair.

Harold, after discovering his friends think he is obese, decides to go on a weight-loss cruise. When he comes back, though, he is noticeably larger.

After Grandpa tells Arnold that he never got his grade school diploma, Arnold convinces him to come to go back to school at P.S. 118.

Arnold and Helga must care for an egg for a school project about parenting. Meanwhile, Rhonda and Harold are project partners and must also take care of an egg.

Helga becomes a model, but she quits after she gets irritated at everyone dressing like her.

Arnold's classmates are tired of constantly telling them the right thing to do, so he stops giving them advice. Nevertheless, when his classmates get into sticky situations, they are in desperate need of his advice.

After getting in a car accident, Bob and Grandpa face off on the golf green, with the loser having to pay for the damage to both cars.

Rhonda attends a finishing school, but is far from impressive with her stroppy attitude, and seeks help from fellow student Big Patty.

Arnold's bland country cousin, Arnie, comes to visit. Arnold begins to notice that Arnie and Lila show interest in each other, making him jealous.

Oskar has to take care of his infant cousin-in-law (also named Oskar), while both Susie and her cousin are gone.

Phil's twin sister comes for a visit, bringing along an unsettled conflict between them.

Arnold and the gang are part of a synchronized swimming team led by Coach Wittenburg.

After eating pork rinds, Helga sleepwalks, uttering her secret about Arnold as she does so.

Arnold, Grandpa, Grandma, Ernie, and Mr. Hyunh compete on a game show against a "perfect" family from PS 119

Arnold tells an urban legend about a decapitated taxi driver. The gang goes out, only to find the details in the story are becoming real.

Arnold and Gerald try to prove superstitions are fictitious, only for it all to backfire on them.

Arnold's Grandpa recalls his adventures as a soldier in the Second World War, outwitting a regiment of Nazis, while Gerald's dad, Martin, remembers his own time serving in Vietnam.

Helga confides in the school psychiatrist about her social life, family life, and her love for Arnold.

Dino Spumoni is found missing and then declared dead after what appears to be a suicide attempt. but Arnold finds out that this isn't the case, and he secretly lives in the boarding house, believing that his work will skyrocket in value after his "death".

While feeling the effects of laughing gas, Helga leaves a confessional message of love on Arnold's phone machine. She then has to get into the boarding house in order to erase the message.

As punishment for shoplifting a ham, Harold is forced to work for Mr. Green at his butcher shop for a week. Later, after his work shift to pay for it is over, he soon learns that he actually likes his new after-school job and doesn't want to stop working there, much to the dismay of Mr. Green.

Arnold becomes a hot (and dangerous) hitter. He keeps injuring people everytime he swings the bat. Afraid of hurting more people, Arnold refuses to play ball. Mickey Kaline helps him out.

Mr. Hyunh has a talent for country singing, so Arnold and Gerald, after recording a CD with him at the local studio, become his managers and make him a big star, much to his dislike.

Grandpa becomes tired of dealing with the boarding house and decides to sell. Arnold has to convince him how important it is for everyone to remain in the boarding house and what they would lose if it was sold.

Gerald's voice is deepened after having his tonsils out, just a few days before the school recital.

Sid pretends that Arnold's room is his, since he's ashamed of showing his real room to Lorenzo.

Patty challenges Helga to a fight after Helga gets on her last nerves by picking on her once too many.

Stinky's simple life changes after he becomes the surprise new spokesman for Ya-Hoo Soda.

Olga gets engaged to a con man who does not exactly woo Helga as he did the rest of her family, but she decides to let the marriage happen so Olga can be miserable. But she is given a change of heart from Arnold, and attempts to stop it.

Curly gets enraged after a minor playground mix up. He locks himself in the principal's office and refuses to come out.

Phoebe wins a chance to meet her favorite singer, only to find out that he doesn't write or sing his own songs.

Grandpa thinks he's going to die soon because no one in his family ever made it past his age. He prepares to die, and Arnold tries to convince him that life is still worth living.

When Bob has to go to a business meeting, Miriam and Helga are forced to go on the family road trip by themselves.

Principal Wartz gives Sid a detention believeing he placed fake vomit so he could trip over, even though it wasn't Sid who put it there. As a result, Sid seeks revenge and reates ""Revenge Doll"" of Wartz's face, like they do in tribes. He thinks he killed Wartz with the curse. Arnold thinks he's paranoid, even though there are a few clues hinting out that Wartz is dead.

A roller coaster breaks down while Eugene and Arnold are at the top of its tallest drop.

After the results of an aptitude test are announced, Harold gains self-confidence and Helga feels dumber.

Oskar gets a job as a newspaper carrier but uses Arnold as cover for his laziness.

Arnold finds out Iggy wears bunny pajamas with feet in them, and Arnold accidentially spills the beans to Sid and Stinky, ruining Iggy's cool image.

Bob hires a nanny to help Miriam around the house, much to Helga's dismay. From this moment on, Helga attempts to scare the nanny away.

A. All the kids are paired with adults with interesting jobs except Arnold, who is forced to spend time with the Jolly Olly, the Ice Cream Man.

Harold is invited to Rhonda's party and befriends the female bully, Big Patty.

The Coach wants to remarry Tish and asks Arnold to be his best man. Along the way, Arnold teaches the coach a thing or two about love and sacrifice.

Rhonda holds a cool-people-only party at her house. In retaliation, Arnold and his friends hold a "geek" party on the roof of his boarding house further up the street, leaving Rhonda's party deserted.

Helga, lost in a love reverie, writes 'Arnold loves Helga' on a wall, but changes the name to 'Lila' when the kids approach. Lila thinks that Arnold loves her until he explains the mistake. Then he falls for Lila and she is forced to break up with him.

The kids compete in a grand prix race against each other.

Arnold and Helga both think they are having the worst Thanksgivings ever. Arnold's Family are celebrating President's Day, and Olga is at the Pataki house. When Arnold and Helga go to Mr. Simmons' house, they discover he has a obnoxious family, so they think their families aren't so bad after all.

Helga tells jokes about her classmates, who take offense to it.

The town is flooded and Arnold's class is trapped in the school.

P.S. 118 is holding a Spelling Bee, and Helga wants to win one trophy to get out of Olga's shadow, but Pheobe has to back out of the competition for Helga to make it.

Arnold, Grandpa, and friends reenact the Pig War.

Arnold is okay with working with Gerald at Mrs. Vitello's flower shop after she's injured and puts Gerald in charge, but not with working for Gerald, which causes the friendship to hit a snag and Arnold quits.

As a science assignment, Arnold and Helga have to work together, and get along with each other, for 24 hours in the Sunset Arms greenhouse.

Arnold has to do a book report, and he decides to do it on his favorite author, Agitha Cawfield, but he sees her bad side when she is very crabby & rude to him.

Lorenzo, a neurotic rich kid, comes to P.S. 118. All the kids try to help him become an average kid.

Arnold snaps at school after Helga tries his patience once too often.

Arnold is in charge of the school dance. He books has-been singer Dino Spumoni, and when he sings a depressing "good-bye" song, all fingers point at Arnold.

The school is doing the play "Romeo and Juliet". Arnold lands the role as Romeo so Helga will do anything to beat out other girls to get the part of Juliet, so that she can kiss Arnold in the final scene.

Arnold and the gang must stop Big Bob from chopping down the oldest tree in town.

When the kids make their new teacher, Mr. Simmons, quit his job, the replacement makes them realize what they lost.

Helga drinks a potion to lose all feelings for Arnold.

Gerald's secret is revealed; he doesn't know how to ride a bike, so Arnold teaches him how.

Arnold and Gerald compete against Helga for the school newspaper.

When Harold is walking in the street, he finds a kitty that belongs to an old lady and he takes it, but then everybody appears, and Harold has to surrender the kitty to the old lady.

Schoolyard tradition has it that on the first Monday of June each year, the fifth graders throw the fourth graders into trash cans. So, Arnold and Gerald try to make a run for it. As more people are thrown into trash cans and the fifth graders know all the routes, Arnold and Gerald find out eluding the fifth graders is harder that they thought.

After Arnold accidentally kills Eugene's fish with a yo-yo, he must do something to make up for it.

An organ grinder's monkey kisses Helga, who's convinced she has caught 'monkeynucleosis'.

Arnold and Gerald do a spot of fishing, determined to catch the pond's biggest fish, the legendary "Big Caesar".

Gerald and Arnold get on the case when Timberly loses her Barney-esque doll.

The new girl is teased at school by Helga and the other girls, but she's soon accepted by everyone.

Arnold and Gerald send the neighborhood alien crazy as they broadcast a mock Halloween radio show.

After Arnold saves Sid from an injury, Sid devotes himself to paying Arnold back with unending kindness.

Arnold and Gerald bunk off school, but their day is ruined by their fear of being found out.

Arnold and Gerald go around the city following "Porkpie", a mysterious man caught on film. They suspect, because of the clues, that Porkpie are planning to kill "Marty", who turns out to be Mr. Green.

In this variation of "The Tell-Tale Heart", Phoebe plagiarizes from a poetry book and uses one of the poems as her entry in a poetry contest. She wins, with her prize being a trophy resembling poet Emily Dickinson. Then, the trophy haunts Phoebe into confessing.

Wolfgang and his gang of fifth graders challenge Arnold and his friends to a football game, but he has to first persuade them that his plays are good enough for them to win.

Gerald, getting tired of his family bugging him, moves out of his home and into Arnold's boarding house, only to realize emancipation is not all it is cracked up to be.

Gerald becomes an entrepreneur out of selling watches until the market becomes saturated.

Rhonda and Nadine fall out over working on a project at school, leaving Arnold to work with both of them separately.

Arnold's Grandpa enters a Chinese Checkers tournament to reclaim his pride lost forty years ago. Robby Fisher's name is a parody of Bobby Fischer.

Helga's mother tries to let her and her father, Bob, bond.

Arnold follows in his Grandpa's footsteps and competes in the annual block party eating contest. After much munching Old Football Head goes stomach to stomach with eating legend Seymour 'The Disposal'.

Rhonda gets glasses and finds out what it is like to be a "Geek".

Helga uses Stinky as her boyfriend to try to make Arnold jealous.

Arnold develops a crush on Miss Felter, a substitute teacher, thinking he is having dinner at her house, only to realize that the one she invited was her fiance, whose name is also Arnold.

Phoebe becomes hall monitor and asks Helga for tips. She becomes overwhelmed by the "power" and soon everyone wants the old Phoebe back, even Helga once she realizes Phoebe's also giving her detentions.

Harold runs away from his Bar Mitzvah, thinking he will retain his childhood this way.

Arnold and his friends get Coach Wittenberg to be their new bowling coach.

The ghost of a former boarding house resident is believed to have been causing strange occurrences in there when Arnold and Gerald find an old pair of glasses believing to have belonged to him.

After finding out that his idol is a haughty, primped actor, Eugene sets out to become bad.

Helga and Arnold fall asleep and have their own "parody/dream" of the opera Carmen.

Arnold and a descendant of his grandpa's arch enemy, Rex Smythe-Higgins, compete in a boat race.

Teachers of Arnold's school go on strike because of inadequate funding; He and his friends are on cloud nine, only to find out that every lost school day will be taken from their summer vacation.

After creating an idea for a parade float, Arnold is confident of it showing up in a parade.

A lounge singer moves into the Sunset Arms after renouncing his songwriter, who also moves there.

Not looking forward to performing in Helga's "The Four Food Groups" musical, Arnold and Gerald decide to take the bus a few stops too many, but end up stuck downtown.

When Arnold accidentally ruins Eugene's new bike, he takes Eugene out on a day of fun, thinking that "every geek deserves his day".

When Helga loses her pink book, full of love poems about Arnold on the bus, it ends up in Arnold's hands. Now Helga must get it back before Arnold figures out who wrote the poems.

The kids are really looking forward to their field trip to the aquarium - especially when they remember the scary Lock Jaw from their last trip. But, when they get there, they see that Lock Jaw isn't really that scary. Arnold notices how neglected the old turtle looks, and returns later with Grandma to set it free.

An obsessed Helga steals Arnold's hat to complete her shrine to Arnold, which is hidden in the back of her closet. But, she notices how miserable Arnold is without his hat, and decides to give it back to him.

Arnold's hat lands on the stoop of "Stoop Kid," - a bully who has lived his whole life on his stoop, and is highly protective of it. But, when it's Arnold's fault that Stoop Kid becomes the joke of the city, he must help Stoop Kid face his biggest fear - leaving his stoop for the first time.

Helga is annoyed when Rhonda doesn't invite her to her slumber party - everybody assumes that "girly" parties aren't Helga's style. So, Helga is determined to prove her wrong, and gets a makeover.

Arnold is asked by his Grandma to help save an old building, and then asked by Ernie to help knock the building down! Who will Arnold decide to go along with? How can he get out of this tricky situation?

Two girls from the sixth grade who are tired of the way that their boyfriends treat them, decide to take Arnold and Gerald to the school dance, but only to make their boyfriends jealous.

Arnold's favorite baseball player is playing his last game, so he decides to go and see his last game. The only problem is that he winds up with terrible seats.

Arnold has a really bad day - the city is suffering from a heatwave, and whatever he does, Arnold just can't seem to get cool.

Snow hits the city and Arnold can't wait to get out and have some fun... but wait, there's chores to be done... and when there done Arnold has the time of his life playing Hockey with the "crew."

At the Annual Cheese Fair, Helga tries her best to keep Arnold well away from Ruth - a girl who Arnold has a crush on.

Arnold and friends decide to clear out a vacant lot to play baseball on, but the adults take over it, and use it for their own reasons.

Arnold attempts to do something that no other kid has done before - completing the entire list of a kid's perfect Saturday! But, unfortunately, things don't go quite to plan.

When the kids complain of being bored, Grandpa tells the story of the Haunted Train. So, the kids decide to go and see if the train exists for themselves.

When Arnold gets mugged in the street, Grandma teaches him how to defend himself, but the training and fighting starts to get to his head.

Grandpa, Arnold, and Gerald are all going on an old fashioned camping trip... until Big Bob, Helga, and Phoebe show up with luxurious camping equipment.

All of the borders get very curious to what is inside the very personal Mr. Smith's package.

Oskar gets kicked out of Suzie's room when they get into an argument, so Arnold tries to get them back together when Oskar moves into Arnold's room.

While Helga tries to find the perfect gift for Arnold, Arnold tries to find Mr Hyunh's long-lost daughter.

An older cool guy befriends Arnold, but Arnold realizes that he is really a shoplifter.

Arnold and the gang play on a basketball team, but their coach tells them to throw the ball to one person, his son, Tucker.

Arnold and Helga compete on a Spelling Bee contest.

When Arnold's pigeon gets sick, he takes it to "Pigeon Man", a person surrounded by pigeons who lives in a rooftop.

Helga decides to give her talented sister Olga a taste of reality by changing her grade in her report card.

Arnold and Gerald must turn off all the lights in the city if they want to see Sally's Comet.

Arnold must find a way to recover his pig pet Abner after he runs away.

Arnold loses Grandpa's watch inside the sewers, so he must retrieve from The Sewer King.

Eugene is accused of pulling the fire alarm. In the school court, the jury thinks Eugene is guilty except for Arnold, who believes there is a shadow of a doubt.

The kids try to get in the book of world records so much that they would do anything, including most people on a one-person bike and the longest game of Crack-The-Whip.

Arnold has a magic show and he makes a disappearing act and uses Helga as the person disappearing. Helga decides to play a trick and literally disappears. She bumps into a pole and has a dream on how the world would have been if she's gone.

Arnold hits Harold with a baseball, so Harold promises Arnold that he'll beat him the next day.

On Valentine's Day, Arnold manages to arrange two dates; one with Ruth, the sixth grader he likes, and one with his French penpal Cecile (actually, it's Helga in disguise) – only for the real Cecile to suddenly appear and Arnold to discover what Ruth is really like.

When Arnold has a Daydream While Playing Baseball Harold Tells him 24 Hours 2 Live (this Episode was Remade Of the Episode Called "24 Hours to Live")