The Big Bang Theory (2007) - 93 mistakes in entire show

Revealing: Most of the time, though not all the time, Leonard has no glass in his glasses.

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

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

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: 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: 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.

Continuity: When Penny is in the shower, there is a red comb on the cistern of the toilet. In the next shot, it has moved without anyone touching it.

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.

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: 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.

Revealing: When everybody is on their laptops at the beginning of the episode, you can clearly see in many shots that their screens are black.

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.

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.

Factual error: Sheldon puts the sword up for sale on eBay. He then says, after only four seconds, that someone had "bought it now". Ebay items take up to an hour to appear in the listings/search results. So in 4 seconds, it was listed, Howard found the item, went through the standard purchasing form and bought the item. There is no way to find, and buy, an item in 4 seconds.

Continuity: At the buffet table when the gang gets food, Howard walks in with his 'date.' Between shots, as he walks in, in one shot Sheldon puts his right hand up on his plate. In the next shot his hand is down.

Continuity: When Leonard and Sheldon are walking downstairs, Sheldon stops and pins back up the caution tape that is in front of the elevator. Between shots, the other strip of caution tape untwists itself.

Continuity: When Sheldon's mom is saying the prayer, the bread roll that Raj is holding swaps hands, and then it disappears in the shot where she tells them they don't have to join in with the end of the prayer.

Continuity: When Penny comes into the apartment to ask if Sheldon needs anything from the market, between the few shots, the position of the napkin and the pile of eggs on the plate he is holding changes.

Character mistake: When Leonard is explaining his thoughts to Sheldon, during the rant which includes him naming who he intends with the words she or her (eg "She: Penny, Her: Leslie), he states, "Indicating that She: Penny had no interest in me asking Her: Penny out," which makes no sense.