Live art: how is it for you?

An alien on a life-support machine sits impassively in a white perspex box, motionless except for the occasional flicker of her empty black eyes. A few yards away, the London Concert Orchestra is tuning up for tonight's rendition of Carmina Burana, oblivious to the extra-terrestrial presence that lurks so near at hand at the Barbican Centre.

The beautiful, scrubbed creature with green tubes up her nose and scleral lenses in her eyes is a 23-year-old art student, Michelle Griffiths. After five weeks of floating in a tank as part of Laurie Anderson and Brian Eno's Self Storage event earlier this year, Michelle has elected to spend four hours a day under boiling fluorescent lighting for her piece Another Preservation of the Lucid Dream, tucked away in the Royal College of Art's painting show.

"It certainly captures the glimpse of your eye, doesn't it?" chirps 13- year-old Ian. Having stumbled upon the show by accident in his lunch-hour yesterday, Ian has come back with schoolfriends Albert and Sean five times already today. Not a glance at the rest of the exhibition, they head straight for Michelle, and stand mesmerised.

Alison Wright, 27, has popped in to watch Michelle after a tip-off from a friend. "It's so much more involving and engaging than looking at a picture," she says. "If you think how bombarded with images you are every day, you're such a passive viewer most of the time. It takes something like this to elicit a reaction. Maybe if I'd seen a lot of performance art I'd be less excited by it, but I'm so glad I came. I didn't see Self Storage, and I just can't visualise it."

With 23,000 people making their way across Hyde Park to see Tilda Swinton recumbent in The Maybe this September, and much of the ICA's "Rapture" season already sold out, live art is suddenly reaching out of its ghetto to new audiences who are discovering the thrill of building up a repertoire of "were you there when..." stories.

The ephemeral nature of live art is both its greatest pleasure and its greatest frustration. "I collect other people's performances and treasure them," says the performance artist Annie Griffin, "but I was envious of artists who had something to show for it." To try and reach wider audiences, Griffin has turned to film for her latest venture, Was she there, in which she travels ostentatiously to Blackpool and then tries to discover if her journey left a mark. "It's a film, but I still feel it's performance art," she says "and still a real experience for the audience."

Marina Abramovic's walk along the Great Wall of China, Karen Finley's yams, Chris Burden nailed to the top of a Volkswagen, Stelarc sewing his eyelids shut, Rose English's horse's erection, Albert Vidal in the chimpanzees' cage... how do we know that the famous moments of performance art weren't purely apocryphal?

Finally pinning down those elusive events is Barry Smith, the director of the Arts Council's new live art archive, based at Nottingham Trent University, but freely accessible on the Internet. Barry has already amassed 80,000 entries, from notebooks and photos to posters and reviews. One of live art's greatest ironies is the zealousness with which its practitioners are now proven to have recorded their work. Could documentation one day replace performance itself?

Michelle Griffiths steps out of her cryogenic chamber and removes her grizzly contact lenses. "I'd love to preserve it, to have a separate me to sit there all the time," she says blinking furiously. "I do document my work, but it's here in the flesh, that's where the impact lies." An Austrian tourist glances at the now-empty cocoon. "Was there something there?" he asks.

n RCA painting show, Barbican, London EC2 (0171-638 8891) to 26 Nov; `Rapture' season, ICA, London SW1 (0171-930 3647) to 3 Dec; `Was she there', Glasgow Film Theatre (0141-353 4589), 20 Nov; Live Art archive (0115 9486831) http://www.ntu.ac.uk/liveart

JUDITH PALMER