Continuity mistake: There is a scene where the Chipmunks and Chipettes are singing the song "Girls of Rock and Roll." In that scene, it shows the boys walking up the stairs together and from left to right the order is: Simon, Alvin & Theodore. The shot goes to the girls then back to the guys. The order of the guys has switched: (left to right) Theodore, Alvin & Simon.
Continuity mistake: In the beginning when the photo of the Master is broken, the pieces of glass change position and then disappear altogether.
Revealing mistake: When Ali Gator and Windy Winston are coming back from the barfight riding the atv's, Ali scratches his head and you can see where the green glove ends and the actors real skin is supposed to be, under the shirt.
Visible crew/equipment: The boom mic is visible when Sally sings her "Pie in the Sky" song and when Courtney and Sally are standing in the bathroom, before Sally's face explodes.