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)
Suggested correction: Michael didn't establish the contract with Hammer-mill. Rather, he locked them up as an exclusive supplier. It's unknown if they were already selling the products to Dunder Mifflin alongside Staples and Office Max.
Wrong, Josh says they cannot sell Hammer-mill products as they are exclusive to Staples so therefore they wouldn't have been able to sell there products alongside as mentioned before until Michael made them an exclusive to them solely, Dunder Mifflin. Therefore the original mistake stands true.