"Treehouse of Horror XIII" finds Homer cloned; Dr. Hibbert turning the family into half animals; and Springfield invaded by zombie cowboys.
Mick Jagger, Keith Richards, Tom Petty, Elvis Costello, Lenny Kravitz and Brian Setzer are the teachers when Homer attends a rock-and-roll fantasy camp.
After testing, Lisa is moved up a grade and Bart is held back so they are both in the 3rd grade together. The teacher thinks Bart is the smarter of the two since he already knows everything. They go on a field trip to Capital City and get left behind and lost.
Marge gets breast implants meant for Mayor Quimby's young girlfriend; Bart and Milhouse spot Krusty the Clown on a old episode of Batman.
The Simpsons end up with termites after going to a hockey game and have to stay out of their house for 6 months. They end up on a reality series where they live in a 1880's type house and life style.
Someone's trying to kill Homer, so Chief Wiggum consults an expert: Sideshow Bob, who moves in with the Simpsons to shadow Homer.
Bart feels sorry for Mrs. Krabappel after she is stood up by Principle Skinner, so he nominates her for an award.
Homer feels bad because he does not know much about Lisa so he hires a private detective to spy on her. He then becomes a big hit with her because of the information.
After she is mugged, Marge retreats to the basement to lift weights. She then becomes obsessed with body building. Marge starts entering contests and her disposition changes as she gets stronger.
Jealous of Ned Flanders winning money at a sports event, Homer starts praying to God for good things to happen then develops a hedonistic lifestyle.
While doing spring cleaning, Lisa comes across a video cassette of a add Bart did as baby "Stink Breath". Bart gets so mad about Homer having spent his earnings from the add that he asks the court to emancipate him from the family.
pelling champ Lisa makes the Spellympics, where host George Plimpton proposes a deal; Homer joins a traveling fan club for a new Krusty food product.
Ned becomes lonely when all the Springfield family's spend a day at the beach with their significant others and ends up dating a actress.
Hoping to reroute air traffic over their house, the Simpsons ask Krusty to run for Congress, where the successful clown finds more of his kind.
Homer's stint in a success workshop gives him new initiative, but Mr. Burns' lack of appreciation prompts Homer to plot revenge, which results in a takeover of the power plant.
Lisa searches for a steady career after a British filmmaker makes her feel inadequate and decides on astronomy.
While looking for a puzzle piece, Homer comes across a letter Marge wrote about how upset she was with Homer right before they were married. He thinks she married him because she became pregnant with Bart and moves out.
Musician David Byrne offers to produce the song that Homer wrote about how much he dislikes his neighbor Ned Flanders. The Simpsons then go to a Dude Ranch where Lisa meets a special boy.
When Homer is trapped, the dog ignores him and he is saved by the cat. Homer then says he has no dog. H.K. Duff, owner of Duff beer makes the Simpsons dog, Santa's Little Helper the Duff mascot.
Homer has his drivers license revoked by Judge Harm which forces Marge to do all the driving for the family.
Busted for a prank gone awry, Milhouse and Bart are enrolled in different youth groups that become heated rivals.
Homer and Marge permit Moe to baby sit Maggie and she takes a shine to Moe, which causes Homer to become jealous.