Continuity mistake: When Mr. Burns tells Smithers that Homer is the next employee of the month, his huge red chair he was just sitting in has disappeared, and Mr. Burns is in a different position. (00:10:30)
Continuity mistake: When Homer apologizes to Moe at the end, he comes in while the door is left open. It remains closed for the rest of the scene. (00:21:05)
Brother From Another Series - S8-E16
Continuity mistake: When in the dam Bob stops the motors from spinning. Next shot shows the blades spinning again, but when the camera cuts they are stopped again.
Continuity mistake: In the scene where Moe is cleaning his window inside the bar, take notice that the size of the spot he cleans on the inside of the bar is small. But when the shot changes to the outside, with Moe and the others looking out from the inside, the clean spot is larger.
Other mistake: At the end when Bart and Homer are singing "twinkle twinkle little star" Bart's tongue is green.
Hello Gutter, Hello Fadder - S11-E6
Continuity mistake: When Homer is talking to Ron Howard on the street, there is no pocket on Homer's shirt. But when he takes the money from Ron, he puts the money in a pocket that suddenly appears.
Moaning Lisa - S1-E6
Continuity mistake: When Marge says, "Oh Homer, you'll lose your head if it wasn't secured to your neck," her necklace is white. However, when she gives the cup cakes to Homer and Bart, it is red. (00:02:00)
Continuity mistake: After the dinner with Sideshow Bob, Patty, Selma and the Simpsons, the food on Bart's plate changes between shots. We first see a piece of meat with some peas, then we see two pieces of meat and some mashed potato. It changes randomly throughout the scene. (00:02:40 - 00:07:05)
Continuity mistake: After Krusty is done doing the special promotion commercial, he is given a telegram informing him of the Soviet boycott. However, this is a flashback, and at this point in time Krusty is illiterate (as will later be established in season 1) so he shouldn't be able to read the telegram. (00:12:30)
Continuity mistake: When Lisa enters the taxi and we see the door being closed, the camera turns into the full view of the taxi in the next shot, and now we see that the door (the one with company logo on it) has changed its shape between shots.
Tree House of Horror II: A Simpsons Halloween - S3-E7
Continuity mistake: When Homer purchases the monkey's paw, you can see open desert to the right of Homer. There was a building in its place a few shots earlier. (00:02:30 - 00:03:15)
Audio problem: When Bart's gang is singing their song and Nelson is playing the banjo, he sings "because she's dead" and plays different notes yet his hands don't move along the neck of the guitar.
Continuity mistake: At Li'l Ludwig's Music School, when Lisa plays her sax she has a rope around her neck, attached to the sax. Then when Lisa yells "You're wrong. You're wrong." The rope has vanished, but is around her neck in the following closeup. (00:05:05)
I'm Goin' to Praiseland - S12-E19
Continuity mistake: When we first see the "Whack-a-Satan" game at Praiseland, there are three rows of holes the little devil dolls emerge from. After Nelson turns towards Flanders, the game is seen behind him, now with only two rows of holes.
Continuity mistake: When Bart and Tab Spangler arrive at the Simpson house, Mr. Spangler points out the belt he is wearing to Bart. But as he leaves Bart and walks to his car, he is suddenly not wearing a belt at all.
Audio problem: When Homer's vigilante group are putting out a leaf fire, Homer says "No burning leaves without a permit" his mouth is not moving.
Continuity mistake: When Bart writes the first letter as Woodrow, he writes it on lined paper. However the letter Edna reads is on plain paper. (00:07:30)
Burns Verkaufen der Kraftwerk - S3-E11
Continuity mistake: When Lenny tells Homer he's the safety inspector, the donut and paper cup have disappeared from his hands. (00:10:05)
Continuity mistake: In the scene where Miss Hoover asks Lisa what the ninteenth-century figure nicknamed 'Old Hickory' is, there is no text on the covers of the book she's holding. In the next two shots, however, 'Teacher's Edition' can be seen on The Front cover and the spine of the book. (00:17:00)
Tree House of Horror XII - S13-E1
Continuity mistake: In the classroom scene in the school Nelson is beating on Milhouse and leaves his head black, but when they go to get graded Milhouse is in front of Lisa (not Nelson) and his head is normal.