The Flaming Lips, The Brighton Centre

A spectacle that rekindles hippie dreams

The Flaming Lips start where other bands end, with an audacious, mind-blowing spectacle. Entering to a Hollywood fanfare, the singer Wayne Coyne rolls over the audience's heads in a giant plastic bubble, turning the tired ritual of stage-diving into a giddy space-walk. Cannons fire confetti and Coyne, released, shoots streamers from a wand. The stage groans from the weight of Flaming Lips family and friends, costumed as Father Christmases, green aliens and superheroes. There are fixed grins all around me, the crowd under wizard Wayne's spell right from the start.

The Flaming Lips have been playing this sort of show for a year now, but its spirit has stayed fresh. It is a benign version of the freaky spectacle they absorbed before they formed the band in Oklahoma in 1983, from violent Texan provocateurs the Butthole Surfers. The Flaming Lips began as similarly underground figures, schooled in counter-culture tradition; Coyne, at 45, is just old enough to remember the Sixties. But with The Soft Bulletin (1999) and the million-selling Yoshimi Battles the Pink Robots (2002), earlier erratic ways were abandoned for more focused experiments.

The Flaming Lips became the first great 21st century psychedelic band, and unlikely, populist holders of America's alternative rock flame. They had been around long enough to experience death and horror, and responded with a simple mantra: to live every day like their last, and to treat rock'n'roll with the playful profundity it deserves, as part of the fight against evil. Naïve as that sounds, they make good on their philosophy tonight.

Coyne, distinguished and charismatic with grey waistcoat and hair, has his hands outstretched and pleading, as "Yoshimi Battles the Pink Robots" presents the first of many metaphors for struggle against cynicism. "The Yeah Yeah Yeah Song" makes this more naked, as Coyne takes time to explain it is about leaders betraying the honour of power, to be sung by the crowd in "anger and frustration".

But it is with "Mr Ambulance Man" that these sentiments find their fullest expression. Its big guitars are backed by explosive visuals and strobe-streaked clouds of dry ice, returning rock to its original, ecstatic intent. With awful irony, as the smoke clears, an epileptic fan can be seen prostrate at the front. Coyne stops the show dead, and the crowd waits respectfully until the woman is safely removed.

The singer's faith in individuals has been movingly proved. An unforeseeable, sickening moment has turned a rock show into an exercise in community, and what follows is a celebration. "Do You Realise?" sees streamers fall from the ceiling, as Coyne asks, "Do you realise, that everyone you know, some day will die?", a nightmare truth expressed with beauty. As balloons roll over the crowd, it feels like a children's party, or the last existential disco.

The Flaming Lips have abandoned rock's moody poses to risk being simply kind. In doing so they have rekindled hippie dreams, and reconfirmed rock's healing power.