
Confidence and Paranoia - S1-E5
Revealing mistake: After Lister faints, you can see him smirk when the cat sings 'S-E-X, I think I've found it!' (00:08:50)

German Week - S3-E6
Revealing mistake: When Mr. Humphries and Mr. Lucas make their toast with the German mugs, Mr. Lucas' mug breaks but Mr. Humphries' does not. A moment later, when Mr. Humphries notices the mug has not broken, you can see that he crushes the mug with his hand.

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.

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.

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)

Revealing mistake: In the wizards versus werewolves special, it's painfully obvious Juliet is a stunt double when she fights and grows her wings.

The Suicide - S3-E15
Revealing mistake: In this episode when Jerry leaves his room to talk to his neighbour about their fight, when he shuts his door the wall shakes revealing that the place he lives in is not a real apartment.

Revealing mistake: Season 2, episode 4 (Duets): When Brittany lifts Artie from his chair and carries him to her bed, right before she puts him down, he is obviously lifting his feet to prevent them from bumping into the bedframe.

Moving House - S3-E1
Revealing mistake: At the beginning when Frank is directing the vans, we see that one gets its windscreen broken by a ladder from another van. However, the glass breaks just before the ladder touches it.

My Journey - S3-E2
Revealing mistake: When Elliot is splashed by the dolphin, if you watch carefully you can see her hair is already wet.

Memories of Cab 804 (2) - S1-E12
Revealing mistake: The gang is talking about their experiences in Cab 804 but when Elaine's segment begins, Tom Selleck gets in the cab and the cab number is 264.

Revealing mistake: A minute or so after the health and fitness instructer dies, we see her lying flat out on her back. If you look carefully, you can see her chest moving up and down and breathing despite being dead. (00:13:05)
Suggested correction: If you actually watch the whole episode you will find she didn't die at all.
Talking rubbish I think, she did die. Maybe you're confusing her with the old lady who fainted?
At what point in the show did they reveal the instructor didn't die? It was the old lady who had just fainted.
I'm a big fan of this comedy and have probably watched each episode 20 times! I struggle to recall any mention of the fitness instructor not being dead.

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: There are numerous shots where "Avid"s ginger hair can be seen coming out of the masks.

Revealing mistake: When Georgia walks into Billy's office naked, a triangle-lamp will cover her "naked" breasts. Look closely, for at one point you can see the white, strapless bra.

Chuck Versus the Gravitron - S2-E8
Revealing mistake: In the scene where Ellie is testing her Thanksgiving turkey by giving Morgan a piece, when she throws it in the trash he says 'no no no Sarah.. what are you doing!', which is the actor's name (Sarah Lancaster), not her character's. Maybe edited in some versions. (00:09:40)

Revealing mistake: In the opening credits, Beefy Bert has a different hair colour to what he has in the actual episodes. This was not included in Series 3.

Revealing mistake: Throughout numerous episodes while the team is supposed to be driving the van, the gear selector can be seen in the "park" position.