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)
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)
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)
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)
Continuity mistake: When the family are driving home from the cinema, Bart draws an angry face on the back of Homer's head. It is never there at any other point in that night.
Continuity mistake: Near the beginning when the family is eating dinner, the glasses on the table keep refilling/emptying themselves, even though nobody takes a drink. (00:03:40 - 00:04:30)
Bart's Friend Falls in Love - S3-E23
Continuity mistake: When Lisa is explaining about subliminal tapes to Homer, there is a robot on the cover of the magazine, whose helmet is yellow. But in other parts of the episode, it is grey.
Continuity mistake: In the video store, when Homer looks at sports tapes, the categories of movies behind him change from drama, horror, and 'Elvis' to drama, western and horror. (00:05:55)
Continuity mistake: At the beginning, if you watch the clock as Homer walks in, the time changes between shots. (00:01:30)
Continuity mistake: The card Bart has written for Milhouse is blank inside. However when Lisa looks at the card, the pun of the joke (on The Front of the card) is now there. (00:01:15)
Lisa's Pony - S3-E8
Continuity mistake: The number of knives that Sherri is holding changes between long and close shots at the talent show. (00:04:50)
Burns Verkaufen der Kraftwerk - S3-E11
Continuity mistake: When Homer is at the vending machine, in certain shots he is wearing a tie and in others he isn't. (00:02:20)
Continuity mistake: After Homer reveals the secret ingredient, one week later, Homer walks into Moe's. In the exterior shot, the door swings open at its right. However, when Moe lights the Flaming Homer, in the next exterior shot, the door swings open at its left. (00:21:00)
Homer Alone - S3-E15
Continuity mistake: When Marge has finished the list of things to do at Rancho Relaxo she has a list on the bed. When we next see Marge a few seconds later, the paper is gone. (00:17:50)
Continuity mistake: Just as Barney asks Homer if he wants to go bowling next Sunday, Moe's boot disappears from the bar and the money appears in Homer's hands off the bar. (00:12:20)
Continuity mistake: When Homer gets off the phone to Moe, all the snacks he had have simply gone beyond a few remaining bits. (00:02:00)
Radio Bart - S3-E13
Continuity mistake: When Bart realises he left a "Property of Bart Simpson" label on the radio we see the camera zoom to the well and down to the radio. However at the top, all the fun fairs, stalls, police tape and people have vanished. (00:14:50)
Continuity mistake: At the bar when Homer is watching the superbowl, his hands keep changing position between the shots. (00:19:00)