Continuity mistake: When the paper falls on Skinner there are blue and white tiles in the doorway, when he is hanging from the hoover, the floor is completely blue. (00:19:20)
Continuity mistake: The paper that Bart draws Skinner on changes from ruled to plain. (00:14:00)
Continuity mistake: When Bart draws Skinner before he is declared missing, the paper is flat on the desk in the first shot and held upright in the next. (00:14:05)
Continuity mistake: After Itchy and Scratchy we see Bart and the mob sat in the bar, the mobster at the end of the bar has his drink in 1 hand or 2 hands depending on the shot. (00:08:16)
Continuity mistake: Bart clears some dust off the picture of the Manhattan, once he's made the drink a few seconds later all the dust has gone. (00:06:40)
Continuity mistake: The drink above the Manhattan on the board changes name and picture. (00:06:40)
Continuity mistake: When Bart falls in the entranceway, a puddle appears under his head between shots. (00:05:30)
Revealing mistake: When Bart is hanging from the play bars his hand goes through the bars. (00:02:35)
Realty Bites - S9-E9
Continuity mistake: The Front door of the Murder House has two windows which vanish, and also a door knob that switches sides so the door opens the opposite way.
Realty Bites - S9-E9
Continuity mistake: Snake has an earring in his right ear, but in some shots the earring is missing then reappears, or it switches to his left ear. Also, when Homer and Snake are fighting on the hood of the car Homer's right shoe falls off, but when the car speeds toward the Murder House, Homer is wearing both of his shoes while he and Snake are still fighting on the hood.
Skinner's Sense of Snow - S12-E8
Continuity mistake: When Skinner dismisses the kids from school, we learn the snow level is near the top of the windows and to the top of the doors. But in the next scene, we see a shot of Springfield and the Simpson home, where the snow level is to the bottom of the door. (00:08:02)
Continuity mistake: Bart is thrown onto his front yard from Sideshow Bob's limo. The campaign buttons pinned to Bart's shirt by Bob's goons in the previous shot have disappeared.
Continuity mistake: Homer draws a face on a punching bag. He starts to show Bart how its done. The punching bag has its eyes filled in now.
22 Short Films About Springfield - S7-E21
Continuity mistake: Lisa comes out of the hairdresser's with a new hairstyle which Nelson laughs at. She is walking away to Nelson's right yet when Nelson's being chased by a tall man later and flees around a corner to his left she's suddenly standing there.
Continuity mistake: Apu grabs the ham and crosses out of the expiration date with a thick black marker. When he places the ham on the shelf the black marker cross out is gone and the writing on the pack looks perfectly printed as before.
Character mistake: Burkina Faso is listed as being among the Southern Hemisphere locations Bart called when Homer is looking over the phone bill; since Burkina Faso is completely within the Northern Hemisphere, it would have made no sense for Bart to call there.
Suggested correction: It may not make sense, but Bart isn't exactly the sharpest tool in the shed. In this same episode, he looked at his globe and thought Rand McNally was a country and was convinced by Lisa that the citizens there wear hats on their feet and that hamburgers eat people. Additionally, he could have just decided to prank call someone there if for no other reason than he thought the name of the country was funny.
Entirely possible, but since Bart had a globe right there to refer to, even someone with his limited geographical knowledge would have been able to tell that Burkina Faso is in the Northern hemisphere, unlike the other locations he did call as depicted in the montage (Antarctica, Argentina, unspecified South American nation, etc).
Continuity mistake: The name card display stand on Homer's desk disappears after Mr. Burns interrupts him.
Continuity mistake: The bikes disappear after Bart and Milhouse arrive at the cave.
Continuity mistake: When Mr Burns and Smithers are standing outside Springfield Stadium, Mr Burns says to Smithers, "Put a little smile on his card" and Smithers is writing it down with a pencil in his left hand. When the Simpsons arrive in the next shot, the pencil has changed into another piece of paper.
Continuity mistake: When Bart says to Homer that he's on "Jumbo-Vision", the man behind Homer is drinking from a paper cup with a straw, but when we see Homer on the screen, the paper cup has disappeared.