Christina Applegate mentions to Fish during the music video shoot that she was in an all girl punk band. When in fact, in real life, Applegate was a founding member of the all girl group The Pussycat Dolls.
When Vesuvius' manager is informing Fish that he is fired from the band, The song "Nobody's Fool" by _Cinderella (IV)_ is playing in the background, specifically the lyric can be heard over the scene: "seems like a thousand years since we broke the ties."
Just before Jeremy enters to tell the group he cant play the prom, Amelia flips off Curtis and drops her arm. In the next shot after Jeremy enters, she is still half flipping him off and her arm sort of just hangs there.
During the first dinner scene, Fish says the last time he saw Matt that he was building a robot. Matt responds that it was when he was 10. Later when Matt is asking fish to drum for them he says that Fish called him Max until he was 11.
When Vesuvius leave the Stage at the end of the movie and A.D.D. reenter it, it can clearly be seen that the drum kit of Vesuvius is covered again and the much smaller drum kit of Fish is on Stage, which wasn't their when Vesuvius started to "play".