Continuity: In the season 2 episode, "The Bad Fish Paradigm", Sheldon starts folding a T-shirt in the laundry room while talking to Penny. However, in the next shot, Sheldon is seen to be folding a sock. There wouldn't be enough time for him to finish folding the T-shirt and start folding the sock.

Continuity: The Tangerine Factor: When Penny is talking to Leonard about who read her Ex's blog, she has a spoon full of ice-cream. Camera cuts and it's now empty.

Continuity: In "The Shiksa Indeterminacy": When Sheldon says that his sister was sent to spy on him, his arms are behind his back. Camera cuts and they are now at his side.

Continuity: The Loobenfeld Decay: Sheldon puts the bag in the bin at the start of the episode so that the handle's are facing the ground. When he gets the bag out, the handles are at the top of the bin.

Continuity: Season 2 Episode 1: The Bad Fish Paradigm: In the laundry room when Penny is talking to Sheldon, Sheldon takes some time arranging a blue shirt on his plastic laundry folder. Then it suddenly turns into a pair of socks, which he folds and then picks up the blue shirt again. There was not enough time for him to switch out the shirt for the socks.

Continuity: Series 1, Episode 17, 'The Tangerine Factor': Penny throws a black Ipod out the window but when Raj comes in he has a silver one. This is a mistake as it's explained that it is the one Penny threw out.

Revealing: Series 1, Episode 17, 'The Tangerine Factor': When Penny goes into Sheldon and Leonard's apartment, to throw the Ipod out the window, it is clear she doesn't actually throw the Ipod.

Audio problem: The Loobenfeld Decay: When Sheldon is knocking on Leonard's door at the start, the sound is out of sync with the action.

Continuity: In the episode "The Tangerine Factor," when Penny is squirting chocolate syrup in the ice cream container, she drizzles some on the lip of the carton, causing it to run down the outside. The camera switches to Leonard and then back to Penny, at which point, the chocolate is gone.

Continuity: When Leonard, Sheldon, Penny, Koothrappali, and Wolowitz are driving at the end to get some dinner, the cars outside are constantly changing drastically.

Continuity: When Leonard and Sheldon are sitting in the sperm bank waiting area, the position of Sheldon's bag strap keeps changing.

Continuity: During the scene where Penny, Sheldon and Leonard eat takeaway and converse, the blue throw hanging over the couch behind Penny continually changes from neat and uncreased, to messy and creased up.

Continuity: When Leonard shouts "Sheldon, sit!" his hand rests on the arm of his chair, then it is off, and then back on the arm again.

Continuity: When Penny sits in Sheldon's seat, the cushion on the other side of the couch rotates itself; evident by the buttons sewn on it.

Continuity: After Penny gets in the shower and throws her towel to the floor, the towel changes position in the next shot, as well as her boots and clothes on the counter as well.

Visible crew/equipment: When Sheldon is mentioning about the coffee table having a garage sale, there is a shot of Leonard with all the stagelights reflected in the kettle.

Continuity: At the end of the episode, when the gang is reading the furniture assembly instructions, a pencil in the cup in front of them suddenly vanishes.

Visible crew/equipment: When Penny is having a go at Sheldon and Leonard, there is a shot of some metal pans with stage lights visible in them.

Continuity: When Sheldon is telling Leonard that he didn't ask Penny out, there is a yellow food-bag on the counter between them that keeps changing it's position with every shot change.

Continuity: When Sheldon, Howard and Raj play Jenga, there is one block sitting at the top of the tower. When Leonard walks in, there are now two blocks at the top, before we actually see Howard place the second one on the top.