Revealing mistake: When Laura picks up Baby Rose from Thomas Stark, the blanket is flipped up and you can see a plastic doll's leg, then when she goes into the bedroom, she has the real baby.
Revealing mistake: While Andy, Aunt Bee, and Opie are at the Hollywood studio watching a scene being filmed, when Andy mistakenly stands up and interrupts the filming we can see the wall and shelves behind the director, and it should look familiar because it's the wall and shelves from Floyd's shop in Mayberry.
Welcome to the Family Part 2 - S2-E25
Revealing mistake: When the family releases Chloe's bubble ability for the last time in the episode the bubble machine is visible.
Revealing mistake: Near the end of the episode, all the castaways are passed out cold when Lord Beasley finally catches his butterfly. Right after saying the line "That's the trouble with you Americans - you simply don't know how to hold your tea" as he's exiting off camera, Mrs. Howell starts to open her eyes slightly, but then quickly shuts them again. Perhaps she thought the cameras stopped rolling.
Revealing mistake: When Shannon walks into the kitchen and gives Stephanie a hug, in one shot of the highchair where Tommy is sitting there is now a doll.
Revealing mistake: In "Not Normal" when SpongeBob says "Hmm. This video tape should help," his left arm is missing. (00:01:25)
The Way We Almost Weren't - S2-E23
Revealing mistake: Closer to the end of the episode, when Lilly and Oliver are lying on the floor glued to the chairs, you can easily see black strips on their backs attaching them to the chairs.
Revealing mistake: In SPD Episode "Sam Part 1" (13-7), when the Ranger first yells "SPD emergency," a piece of Jack's Morpher breaks off.
Double, Double, Toil and Trouble - S4-E4
Revealing mistake: As Serena gets hit by the pie her real blonde hair shows underneath, also, she wears minimal make-up for the only time.
A Man's Teeth Are Not His Own - S2-E13
Revealing mistake: When Rob is "playing" the piano none of the keys on the piano look to actually be pushed down. Also when he's scratching his back with each of his hands the notes on that same side of the piano are still played. He's not actually playing the piano. (Except for the last 2 notes or chords). (00:02:46 - 00:03:27)
Revealing mistake: At the Brown Derby, when Lucy bumps into the waiter causing him to trip and spill the tray all over William Holden, we can see that the waiter's hand is taped to the bottom of the tray for the stunt to be done efficiently. (00:15:15)
The Fresh Prince Project - S1-E1
Revealing mistake: When Will staples his Malcom X poster to the wall, the wall bends back and forth for a second or two.
Revealing mistake: When Arnold's burns down you can see the set walls wobble a lot.
Revealing mistake: In the wizards versus werewolves special, it's painfully obvious Juliet is a stunt double when she fights and grows her wings.
Revealing mistake: When Peter is on the trampoline, instead of saying "Peter," Carol says, "Go get 'em, Chris!" and a few minutes later the same thing happens after Cindy has a turn alone, you can hear Greg say "Why don't you give it a try, Eve?" (00:18:10 - 00:19:50)
Clash!! Sonic VS Knuckles - S1-E5
Revealing mistake: Right at the end of the episode, when Amy is telling Knuckles he should apologize, Amy has two right hands.
The Library - S1-E3
Revealing mistake: In the extra 'Library' scene, the book that Bean is given already has the loose pages before he has been at them with the knife. (At one point the pages get pushed forward a little bit, meaning that they're not fastened into the book.)
Revealing mistake: In almost every episode where Michelle is a toddler, you can always see her look to the right or left to most likely a person telling her what to do.
Revealing mistake: Samuel Clemens (Mark Twain) spends a night in North Fork while the wheel of a stagecoach he is riding in is being repaired. Clemens is fishing at a lake and Mark McCain says, "You've caught a fish " Clemens tells the boy to reel in the fish. The boy jerks the rod and pulls the fish out of the water. The fish is obviously a fake which a stagehand had attached to the hook. The fish is motionless and is not even wet.
Revealing mistake: After Sam shoots Spencer with her blowgun, she lands on the ground after jumping from the ceiling. During this shot, you can easily see that it is a stunt double.