Rock and Roll as a musical form lends itself well as form of expression to teens and young adults. It's cord structures and arrangements tend to be easy enough to understand and the basic instruments (guitar, bass and drums) are not difficult to play with a little practice. Rock could be considered the "folk music" of our culture, meaning a musical form that bubbles up from the people and requires no special training (and sometimes little talent). It's all about passion.
The rock band U2 is arguably the most famous band on earth. But everyone has a beginning and everyone starts as a child. The members of U2 were first playing together in 1976 when Bono, The Edge, Adam Clayton and Larry Mullen Jr. were 14 and 15. Here are a couple of early U2 videos that show the group as teenagers. Although these songs arguably aren't too good yet, they are fun to watch and see how one of the biggest bands in the world got started.
"Street Mission" - U2
"Life on a Distant Planet" - U2
Stories for Boys" - U2
What'cha think?