http://www.youtube.com/watch?v=2Vut1aWPlnA
In this 1987 episode of Family Ties, Jennifer starts a band which successfully auditions to play at a school dance. However, Alex decides to manage the band and causes a lot of friction, presumably because Michael J. Fox is still bitter that his band wasn’t allowed to play at the school dance in Back to the Future because they were too darn loud (hell, Fox looks like he’s wearing the exact same suit that he wore to the dance in BTTF). Anyway, look for an unknown Christina Applegate playing the keyboard in Jennifer’s band during these scenes.