Continuity mistake: 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. (00:06:30)
Continuity mistake: When Sheldon emerges with all of the bath item gift baskets for Penny, he drops them on the floor and chair. Between shots one of the baskets on the chair changes from being an upright green-ribboned basket, to a toppled-over white-ribboned basket. (00:19:50)Hamster
Continuity mistake: Near the start, when the camera is on Raj, David Underhill is seen in the top left-hand corner of the screen shaking someone's hand, already in the cafeteria. Then, when the camera is on Wolowitz, David is just walking into the door of the cafeteria. David sits down to the right of the man sitting at the table, then shortly afterwards David is now sitting where the other guy was, originally.
Continuity mistake: In the opening scene, just after Howard says, 'Creepy good or creepy bad?', there is a shot where Howard is holding his food, even though Leonard hasn't given it to him yet and it isn't there in the shot before or after. After Leonard gives the food to Howard, the exact same shot is used after he says, 'I'm not necessarily talking about the food', so the shot was taken from there and it is shown twice. (00:00:25)duncanmc