Continuity mistake: When the girls take Sheldon out dancing, he mentions that he considers himself a proficient dancer due to his Cotillion training when he was a boy. But in S1E7 The Dumpling Paradox, when Leonard suggests that they could have gone dancing with the girls, Sheldon said that nobody in the group - including him - could dance.Moose
Continuity mistake: 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. (00:04:50)Boobra
Continuity mistake: When Sheldon and Leonard are in the kitchen discussing Leonard's upcoming night out with Mrs. Latham, there's a plastic bottle of orange juice on the table that keeps disappearing and reappearing as the camera switches between Sheldon and Leonard.