Jack Black's twin careers as actor and rock musician merge in this fantastical tale of his band's humble beginnings and the search for the demonic guitar pick that will turn them into rock gods. He's joined in his quest by fellow Tenacious D band member Kyle Gass, and ropes in cameos from real-life rock gods Meat Loaf (as his dad), Ronnie James Dio (as his heavy metal muse) and Dave Grohl of the Foo Fighters (as Satan!). If those names mean nothing to you, then this is probably a movie to miss. But if they do, or if you're a Jack Black fan, then this may well float your boat. It's an over-the-top and endearingly self-indulgent slice of Spinal Tap-style self-mythologising that sadly, after a wildly funny start, rather runs out of comic steam.

In Venice Beach, naive Midwesterner JB bonds with local slacker KG and they form the rock band Tenacious D. Setting out to become the world's greatest band is no easy feat, so they set out to steal what could be the answer to their prayers... a magical guitar pick housed in a rock-and-roll museum some 300 miles away.