Continuity mistake: As Homer is carrying the TV towards the pawn shop in the first shot the left window is clear. There is then a tracking shot of the family walking and when they get in front of the store the window has writing on it saying Pawn Shop. The writing is in black and the next shot when they are talking the writing is now dark brown. (00:14:20)Lummie
Continuity mistake: When Homer goes to work, and Mr. Burns starts complaining about him, we can see that the two pictures are on the far side of the yellow machine on his desk. But then when the shot changes, they are on the other side of the yellow machine. (00:13:45)Chaz1003
Continuity mistake: In 'Time and Punishment,' Homer goes back in time, then returns, and the kitchen table has plates of food, cutlery and glasses all set out. Then when Homer is informed that Ned is the Lord of the Universe, the house starts shaking, but you can see the table is now totally clear. (00:11:15)Hamster
Continuity mistake: At Asa's funeral Burns and Grandpa both produce a key to unlock the compartment in the Hellfish monument, but even though they both take their keys out of the keyholes after turning them, all 9 keys are in place in the following shots.
Continuity mistake: When Marge arrives home complaining that she is too tired to talk, there is an alarm clock on Homer's night table. When first shown it is a black electric clock, but when it is shown in the very next scene, it is an old orange one. Only a few seconds passed between these scenes, meaning there was no time for anyone to change it.