At what point did the appearance of 24 voluble Americans wearing white robes, grinning maniacally and proffering cheesily vague exhortations ("You gotta be good, you gotta be strong") cease to be a cue to run to the hills? Surely the success of the Polyphonic Spree can't only be testament to the enduring appeal of dressing up and mucking about?

The band troup on stage to the sound of a lone organist, somewhere between a twee cult and an overgrown Sunday-school outing. At least they have a song, which is more than many bands manage. Unfortunately, it lasts for over an hour and appears to have been extrapolated from the toenails of the Flaming Lips. Or, perhaps, it's something from Mercury Rev's Deserter's Songs, boiled for 150 years and spread incredibly thinly over an enormous amount of very white bread. To be fair, parts of the set do seem to be slower than others - which would seem to indicate that several different songs have been arranged in a way that makes sense to the band - but there is a such a deal of stopping, starting, vamping and self-consciously quirky tempo changes that it is hard to tell where one pale copy of something ends and another one starts.

Tim DeLaughter, the man around whom this chaos doesn't quite coalesce, has the speaking voice of a particularly saccharine Walton, and is given to thrusting both arms in the air in a messianic fashion. Band members bounce up and down and toss their hair, intent, no doubt, on communicating the rapture of the enterprise. It is (pay attention at the back) uplifting; it is jaunty; it begs that most benighted of adjectives: wacky. The fascistic pressure to join in and have fun, when what's on offer doesn't really look like fun at all, hangs heavy.

There's barely a chord on show that proves they are worthy of comparison with the 1960s pop they seem to see as their precedent. They seem to have confused the elegant art of singing harmonies with the mewling reality of a bunch of people who just sing at the same time. Certainly the horns sound mighty fine, but then horns generally do - it's just that you don't encounter them that often. Surely this accounts for the band's initial appeal to jaded, London music-industry types: no one had seen anything like this before. Did it really matter whether it was any good?

The band churn on: a terrifying summer camp for recovering alt-rockers performing an interminable Jesus Christ Superstar medley. Is rapture really meant to look like such hard work?

· At Leas Cliff Hall, Folkestone (01303 253193) tomorrow, then touring.