School Of Rock (2003)

Genre: Comedy | Family | Music
Director: Richard Linklater
Starring: Black, Mike White, Joan Cusack, and Adam Pascal
Tagline: Take Notes.
Plot: A wannabe rock star in need of cash poses as a substitute teacher at a prep school, and tries to turn his class into a rock band.

Description:
Down and out rock star Dewey Finn (Black) gets fired from his band, and he faces a mountain of debts and depression. He takes a job as a 4th grade substitute teacher at an uptight private school where his attitude and hijinx have a powerful effect on his students. He also meets Zack, a 10-year-old guitar prodigy, who could help Dewey win a "battle of the bands" competition, which would solve his financial problems and put him back in the spotlight.

http://www.imdb.com/title/tt0332379/
http://en.wikipedia.org/wiki/School_Of_Rock