Lecture Circuit: Part 2 - S5-E15
Continuity mistake: When Jim and Dwight are talking about the activities for Kelly's party, Dwight is attempting (horribly) to blow up a silver balloon. Just after Jim finishes reading The List of proposed activities, Dwight says, "You're right, forget horse hunting, it's stupid." Immediately after he says this, the shot changes and he is now holding a brown balloon. (00:16:30)
Answer: In the 2007 episode "Ben Franklin" when Jim is talking to Pam there is a candy bar with a purple wrapper that says "Picar-" I assume picaroon, it's hard to see past Pam. I found this trying to investigate what that candy bar is lol.