Heavy rock: Music made by the intellectually challenged for 13-year-olds. To be sung as if your nads are in the process of dropping. It's funny: finally people have realised this, chuckling 'ironically' as they buy Darkness records and now enjoy the broad comic strokes of School Of Rock, which is directed by the highly unlikely figure of Richard Linklater. It's set alight, however, by the highly broad figure of Jack Black, a man who can't help but be funny in everything he does.