Don't speak to me of cool. True cool is like Zen, the harder you try, the less likely you are to achieve, and if you try too hard, large bald monks whack you upside the head with bamboo sticks. Or, rather Fonda 500 should whack you upside the head with casiotone keyboard.

But don't you know? Pop moppets and RAWK bands in leather jackets are OUT! 17-piece psychedelic arkestras in quasi-religious costumes with string quartets and horn sections and random carollers in 8-part harmony are IN! They Came From The Stars I Saw Them (I'm not even going to attempt to punctuate that) are somewhere between a free-form avant-pop collective and a cult. Polyphonic Spree comparisons are unavoidable, but, wide-eyed and sparkling, the result is like a grade school glee club whose punch-bowl has been spiked with LSD. Lisa "I can see through time" Simpson would be proud.

When was the last time you felt that sort of kid-on-Christmas-morning type of utter rolling-in-the-snow abandonment, without the aid of drugs or drink? I'll tell you the last time I felt it - in the front row of the Barfly, as Fonda 500 came onstage and launched immediately into 'Super Chimpanzee'. Last week, at the Drowned in Sound Xmas party, they were disorganised and ramshackle, the victims of poor sound. Yet through sheer energy and winning charm, they managed not just to steal the show with their frenetic pop smorgasboard, but to deliver one of their best shows of the year. Tonight at the XFM Xmas party - razor-sharp, focused and tight - they manage to be even better.

Helplessly odd, wildly experimental, delightfully weird without ever being wilfully arty or pretentious - Fonda 500 encapsulate everything that I believe in music. Stomping kraut-disco dance anthems like 'Roller Disco' and 'French Brothers And Sisters' fight for space with lost bubblegum pop classics like 'Super-Chimpanzee' and recent single, 'The Colours And The Birdsongs'. Hip-swivelling 'Robot Rhumbas' soundclash with human beat-box solos. There are very few other bands in the world that pull off such wide-ranging and often contradictory influences (dronerock, electro, hip-hop, 60s bubblegum, psychedelia) - the only other bands even in the same ballpark are major-league nutters like the Flaming Lips and Super Furry Animals.

London audiences are notorious, Barfly audiences even moreso, for standing with their arms crossed over their chest waiting to be impressed. Yet by the third song, heads are nodding and toes are tapping. By the end of the set, the entire audience are on their feet, arms aloft, cool forgotten, screaming like children who have just woken up to find the biggest present on the Christmas tree.

Nothing can possibly top this, but just as Gold Chains are about to go on, I run into Miss AMP, who grabs me by the wrist and pulls me up front. This is a bad sign. The harsh squeak of a 303 being abused, like a minimalist Peaches backing track announces the arrival of a short, fat, bald white bloke with thick glasses who proceeds to start rapping, presumably about being a short, fat, bald white block with thick glasses from San Francisco. As this encapsulates just about everything I HATE about music, I run downstairs to hide in the bar. John Kennedy even plays me a track from The Sonics' Xmas album. Hooray!