As anyone who watches Top of the Pops will tell you, dance music has appalling presentation problems. Week after week, dance acts humiliate themselves on prime-time television.
The formula is invariable: a phalanx of gormless dancers, perhaps a punchable rapper or two, while at the back of the stage, the least visually prepossessing man in the history of music television - the one who actually made the record - feebly prods a synthesiser or pretends to DJ.
Over the years, there have been several diverting attempts to overcome dance music's hopeless on-stage image: the Prodigy's preposterous punk pantomime, Orbital and the Chemical Brothers' epic son-et-lumière. On the evidence of tonight's gig, Australian DJ collective the Avalanches have come up with a new solution: they become an entirely different band on stage.
Their rightly lauded debut album, Since I Left You, was a painstaking construction, hundreds of quirky samples stitched together to create a unique hybrid of hip-hop, psychedelia and pop. Live, however, it's all guitar-flailing abandon. Album highlights - the Madonna-sampling Stay Another Season, the gorgeous title track - are cheerily demolished by waves of distorted effects and frantic, punky thrashing.
Members of the Avalanches sport a variety of ridiculous hats, swap instruments and indulge in tongue-in-cheek rock posturing. One member's entire role seems to consist of jumping up and down while frantically waving his arms.
Occasionally they stop playing altogether and a DJ plays records apparently chosen at random - Marvin Gaye's What's Going On, the theme from Mash, ELO's Living Thing. The audience react with faintly bemused delight.
It looks less like a dance act than a bunch of people who have wandered on stage by mistake shortly after closing time and, spurred by Dutch courage, have resolved to stay put. It's shambolically entertaining and thrillingly unpredictable, lacking in finesse but brimming with good-humoured brio.
For an hour, you never know what's going to happen next. Best of all, it's about as far removed from the bland conformity of most live dance acts as it's possible to get.
The Avalanches play the Electric Ballroom, London NW1 (020-7485 9006), on August 22.