Bart the Genius
The Simpson family spend a night of playing Scrabble and Lisa reminds Bart that he is supposed to be stimulating his brain with various vocabulary if he hopes to pass his intelligence test. He cheats his way to victory by coming up with his own word, basing its definition on an insulting description of Homer. This angers his father and he spends time chasing after Bart, much to the embarrassment of his family.

At Springfield Elementary School, Bart is busted for vandalism by Principal Skinner, who has been informed by class genius, Martin Prince. Faced with the prospect of failing an intelligence test, Bart surreptitiously switches exams with Martin. When the school psychologist, Dr. Pryor, studies the results, he identifies Bart as a genius, to the delight of Homer and Marge, who enroll him in a new school. However, Lisa is not fooled by his supposed genius and still believes Bart to be a moron; Skinner shares her belief, but takes advantage of Bart's departure from the school.

At the Enriched Learning Center for Gifted Children, Bart feels out of place among the other students with advanced academic skills. Meanwhile, Marge attempts to stimulate Bart with a little culture by taking the family to the opera. However, this proves disastrous as Bart and Homer are quite disruptive, much to Lisa's joy. Ostracized by his brilliant classmates, Bart visits his former school, where his old friends reject him because of his perceived intelligence. On the bright side, he enjoys newfound attention from Homer and he covers for them when Marge makes another attempt to stimulate Bart's brain by taking to a ballet recital. After Bart's chemistry experiment explodes, filling the school lab with green goo, he confesses to Dr. Pryor that he switched tests with Martin. Dr. Pryor realizes that he was never a genius and has him readmitted to Springfield Elementary.

Bart returns home and tells Homer that he cheated on the intelligence test, but that he is glad they are closer than ever. An angry Homer chases Bart through the house, only for Bart to lock the door of his bedroom. Lisa pronounces that Bart is back to being his normal, dumb self.

Itchy and Scratchy: The Movie
Marge and Homer go to Parent Night at Springfield Elementary School. Although Ms. Hoover tells Homer that Lisa is doing well, Ms. Krabappel tells Marge that Bart is continually causing trouble. Urging Homer and Marge to enforce stronger discipline on Bart with the idea that he could grow up to become a Supreme Court Justice if he turns his life around, the two return home to find that Bart stole and broke Grampa's false teeth. As a result, Bart is sent up to his room without dinner as punishment, but Homer sneaks up and brings him some pizza, making Bart promise to behave. However, Bart continues to get in trouble and Homer's attempts to discipline him fail. Eventually he promises Marge to make the next punishment stick.

It is announced that there will be an Itchy & Scratchy Movie and in anticipation, Bart buys himself a ticket. Later on, Bart is left to babysit Maggie and he neglects to watch her as he is distracted by the history of Itchy & Scratchy, leaving her to take Homer's car for a joyride and crash into the wall of Springfield Prison, releasing the prisoners. As a result, Homer angrily blames Bart and punishes him by banning him from ever seeing The Itchy & Scratchy Movie. He tears up Bart's ticket to prove that he means business. Bart begs to be given a different punishment, but Homer refuses. After the film's release, Bart becomes angry and sad that he is the only kid in Springfield who has not seen it. Two months later, the film is still being shown in theaters as Marge and Lisa beg Homer to change his mind, with Marge claiming Bart has been punished enough. However, Homer still denies this and makes the punishment stick. Bart attempts to secretly watch the film by paying for a ticket, but finds out that Homer went to the theater and requested that the employees there not sell a ticket to him. Eventually, the film is removed from theaters and Bart tells Homer he won, to which Homer replies by saying they both won because by using his punishment Bart is in no doubt headed for a better life.

40 years later, Bart, now Chief Justice of the United States, and Homer, a senior citizen, walk down the street and discover the film is back in the local theater as a classic re-release. Homer decides that Bart has learned his lesson and the two watch the movie happily together

I&S:TM hits that rare sweet spot between really funny and really sincere.

Although to be fair, so does Bart the Genius...

Man, that part when he shoes up at the school for gifted kids?
"Oh, don't mind Sidney. He's just speaking in backwards phonetics today."

And that classic scene of Bart running naked covered in turpentine?

I'm changing my vote.