Bart Carny - S9-E12
Continuity mistake: When the Simpsons drive up to the house, there are no boards on the window. When they can't get in, suddenly there are boards on the windows.
Treehouse of Horror XV - S16-E1
Continuity mistake: When Maggie crawls out of the stroller and into the capsule, the stroller has no harness, but when Marge sees the empty stroller, there is a harness.
Who Shot Mr. Burns? (2) - S7-E1
Factual error: When Chief Wiggum opens the revolver's chamber, there's 5 rounds with one open slot. In the next shot, we see the reverse end of the chamber and it's drawn in such a way to indicate those 5 rounds all have bullets in them still, meaning the empty slot is from when Maggie shot Mr. Burns. But revolvers don't eject spent shells automatically and no one handled the gun after it dropped on the floor. So the empty casing should have still been in there when Wiggum opens it up for the first time.
How Lisa Got Her Marge Back - S27-E18
Continuity mistake: The pictures of the celebrities behind Lisa and Andrew Rannels change position depending on the whether scene is focusing on Lisa or Andrew.
Who Shot Mr. Burns? (2) - S7-E1
Character mistake: Willie says he got arthritis from playing Space Invaders in 1977. However, Space Invaders didn't come out until 1978.
Other mistake: When The Town is singing the Christmas carol you can see Sideshow Bob, who was arrested and jailed in series 1. We know he hasn't been released, as that's a plot point over the show. (00:18:10)
Two Cars in Every Garage and Three Eyes on Every Fish - S2-E4
Continuity mistake: When Marge is standing outside the Kwik-E-Mart, she is holding some papers with a picture of Mary Bailey and the words "Re-Elect Bailey." But in a long shot of Marge in the next shot, the papers she is holding in her right arm are now completely blank.
Some Enchanted Evening - S1-E13
Continuity mistake: When Ms Botz is leading Bart, Lisa and Maggie to the living room, the video she is carrying in her hand is brown. In the next shot, it is now blue, and when she is talking to Bart, it is brown again.
Tree House of Horror VII - S8-E1
Continuity mistake: In Citizen Kang, when Homer bursts in at the Dole-Clinton Debate, you can see the wall behind him is light blue, but when we see a close-up of Homer, the wall is now brown.
Continuity mistake: When the Simpsons are at the restaurant at the start, Bart has no medal on his jacket. But when Lisa remarks a few seconds later that Homer gave Bart a medal, one has appeared on his jacket.
Continuity mistake: When Stefan starts crying at the football, Marge puts some music on and Homer's Sadgasm band appears on the radio. At this point, Stefan's wine glass is in front of the couch on the floor. Stefan then says he needs whale songs - Marge puts an "Oceans of the Sea" CD in the CD player and the wine glass in front of the couch suddenly vanishes.
Continuity mistake: The house is ripped from its foundations, but later on when it falls down the waterfall you can see the floor is completely intact.
Continuity mistake: When Homer gets out of the electric chair, the sponge has disappeared from on top of his head.
Revealing mistake: In the scene where the family is in the car, driving home from The Town hall meeting, Homer says "the whole reason we have elected officials is so we don't have to think all the time!" When he says "don't" a second collar appears beneath the right collar of his shirt, and then disappears after he says "time." (00:11:20)
Eternal Moonshine of the Simpson Mind - S19-E9
Continuity mistake: Near the end, when Homer says "I'm a genius", Krusty is seen with yellow skin, but is later seen with his usual white skin.
Continuity mistake: When Marge enters "Your home from space" the address is still http://www.google.com, then the shot changes to Marge outside and then shows the computer again where the address is now http://yourhomefromspace.com.
How Munched is That Birdie in the Window - S22-E7
Continuity mistake: Right before the Itchy and Scratchy Show episode starts, Santa's Little Helper is colored in a much darker shade of brown than usual.
Continuity mistake: When Bart says "Stop feeling sorry for him", Dr. Robert Terwilliger Sr. is seen sitting in the audience, even though he is supposed to be sitting in the witness stand.
Continuity mistake: When the jury is "oohing" Wallace Brady, Lenny's five o'clock shadow is missing. It reappears in the next shot.
Continuity mistake: Milhouse's hair is blonde in the school bus' mirror reflection.
Suggested correction: Maybe he was allowed to participate due to good behavior. That's a possibility.
Rubbish. He is denied parole numerous times and shown to be a high risk prisoner.
Ssiscool ★
Good behavior or not, a prison wouldn't furlough an inmate just so they could participate in a snow day.
Phaneron ★
I'm not sure if it's been discussed here or listed as a mistake. Part of the problem with "The Simpsons" and the Sideshow Bob character is that time both moves forward and doesn't move. In "A Brother From Another Series," Krusty visits the prison and tells Bob he hasn't seen him in years because Bob had been in prison all those years for his crimes. Yet Bart and Lisa are still the same age and in the same grade. Bob is also let out of prison on a work-release program in the episode.
Bishop73