When a documentary is as entertaining as Air Guitar Nation, you have to ask if you really need it to have redeeming social value or to advance the art form in any way.

This raucously entertaining documentary about one of the silliest competitions on the planet actually has a serious message about the power of "airness" to change the world. Well, maybe.

There must be better, more useful ways of amusing themselves but obviously none which would allow them to strut the stage to the plaudits of a baying crowd like latter-day rock stars.

Very funny.

Like most guitar solos, the film doesn't quite know when to quit.

Originality 0.9, Presentation 2.3 and Silliness 5.2.

Despite the film’s admirable brevity it’s still hard to maintain a wry ironic grin for a full 81 minutes.

While quite possibly the stupidest thing you’ve ever seen in your life, this documentary exploring the world of air guitar enthusiasts is a riot from start to finish.

A gloriously insane journey into the weirder reaches of rock, Air Guitar Nation is a funny, funky and oddly moving burst of lively factual entertainment.

Shot in a raw, grungy style that lends the film a degree of authenticity, AGN is a riff-roaring experience that rarely hits a bum note.