This is the most entertaining film about Australian music, and the nature of some Australian men, that I've seen in a dog's age. It is much more informative about the latter than the former, principally because Knight is an interesting combination of contradictions, a hard nut with many layers of protective armour. He describes himself as ''just a f---king farmer'', and a man ''with a head like a robber's dog'', but neither is true.

In fact, none of what he says is the whole truth. That's part of what makes him interesting: like a novelist, some of his utterances are an inventive way of looking at the truth, others help him to stay away from the term ''artist''. The force of anti-intellectualism is strong in Knight, as in many Australian blokes. His songs may be about dead roos and loving his tractor, but this farmer, who just wanted to be in a band so he could get free beer, has been writing songs for 30 years, some of which have had big covers.

The band's friends and admirers include Eddie Vedder of Pearl Jam and Buzz Osborne of the Melvins, who describes the Psychos' music as sounding ''like late '70s punk rock played through a stereo inside the muffler of a car dragging down the freeway''.

This film takes a funnier and less respectable approach to its subject, with many diversions to record outrages on the road. It's a joyful and anarchic history of a bunch of blokes who like beer, bulldozers and music that sounds like a headbutt. Eye shadow was not required.

The band's precursor formed in high school in 1977 - a three-piece punk band made up of ''the only three punks in Kyneton'' - Knight, Steve Morrow and Robbie Addington. They called themselves Rancid Spam and no one liked what they did. Morrow and Knight moved to Melbourne, where they met drummer Bill Walsh. That band was called Spring Plains, after the area where Knight's family has long owned a farm. Peter Jones replaced Morrow on guitar.

Knight had been known as Psycho all through school, and Walsh was ''Cosmic''. Jones' nickname was ''Dirty''. The Dirty Cosmic Psychos soon became just the Cosmic Psychos. Knight did not like the name until he heard that a member of Split Enz hated it. That made him like it more.

Down on the Farm

Jones and Walsh quit, to be replaced by Robbie Watts and Dean Muller. Watts died of a heart attack in 2006, after years of heroin use, and was succeeded by John ''Mad Macka'' McKeering. This guy usually performs topless, or in underpants. For his interview, the director taped the microphone direct to his bare chest. Spinal Tap all over.

Melbourne-based Matt Weston has made more than 100 music videos. His approach here is light, rather than analytical. Not much music history, but a lot of high jinks, humour and alcohol. The serious stuff - marriage breakups and band tensions - is barely mentioned.

Knight is serious only about a couple of things: his love of his children, one of whom is severely disabled; weightlifting (at which he has won several world championships); and the death of his friend Watts, whose grave he visits regularly. He takes two stubbies of Coopers Sparkling (Watts' favourite), one of which he upends in the soft soil of the grave. It's a sentimental gesture from a man who shows few of them.