Continuity mistake: When Spinelli is challenging the hustler kid, she asks for Gretchen's bow (for a blindfold). In the shots after that, Spinelli is still blindfolded with Gretchen's bow, yet Gretchen is still wearing it.
Continuity mistake: In the time before King Bob tells his story about being the Prankster Prince, no one is on the jungle gym except TJ and his friends. But after Bob finishes, around 20 kids are on the jungle gym, plus TJ and co. There was not enough time for ALL those kids to get on top of the jungle gym from the time King Bob started his story to the time he finished.
Continuity mistake: Gretchen starts talking to that man who doesn't talk, but later when Mikey is singing for the first time, you see that man booing him, then a minute later Gretchen is still talking to him.