Continuity mistake: When Randolph is bombarded by reporters after framing Sheldon, someone throws an egg and his head is all slimed after the egg breaks. However, in a few quick shots after the egg hits him, the amount of egg on his forehead changes shot to shot from quite a bit to very little, and then when he finally gets in the car, there is no trace of egg on his head.
Visible crew/equipment: In the ice skating scene at the end of the movie, Shelton and others are saying good bye to Smoochy. Buggy fires, and the camera goes to Shelton falling to the ground. If you look at Shelton's head, you can see the special effects tub that shoots air (or something) out, to give the impression a bullet has just gone into Shelton's suit.