""Don't look at your fingers. Girls look at their fingers,"" music teacher Paul Green snarls at one student, ""Do you want to be in the Bangles?"" Failed rocker Green is a documentarian's dream. A bubbling ball of ego on the point of explosion, the proprietor of Philadelphia's modestly entitled Paul Green School Of Rock Music incessantly bellows insults and derision at his 8-to-18-year-old students. So much so it's surprising that one of them doesn't garrotte him with a guitar string.

A mix of interviews, classroom scenes and footage of their trip to Germany to take part in a bizarre Frank Zappa festival, Don Argott's patchy film is as furiously OTT and enjoyable as an AC/DC💞 guitar solo. So what if a little more background on Green would have been nice? Even if♒ we don't know what makes him tick, the overbearing svengali's monstrous presence gives this familiar tune a rattling good hook.