Amid a sensory blizzard of pounding music, revolving back-projections and dazzling arc-lights, a quartet of enigmatic figures emerges from the primal fug of dry ice. What imposing gladiatorial spectacle is it that we are to be offered? Nothing less than four comedians making stuff up as they go along.

You can see the logic behind One Word Improv's grand opening. If ever a comedic genre has been in need of a glamour injection, improvisation is that genre - the televisual novelty of Whose Line Is It Anyway? having now worn off to such an extent that controlled screenings are being used by the Special Branch to extract confessions from tight-lipped child criminals.

The high-glam approach seems to be working too, as the Albery Theatre is still happily full five weeks into the run. But what of the show itself? Surely it's not so much flogging a dead horse as disinterring its long-buried corpse and parading it through the streets dressed as a clown?

The four performers come supplied with mythological epithets. There's Mark "Carling Black Label advert" Frost; Neil "Once worked with Mike Myers of Wayne's World legend" Mullarkey; Suki "No previous form to speak of" Webster; and last, but definitely not least, Eddie "Never off the bloody TV" Izzard. Initially, as the audience's one-word suggestions compete for the improvisers' straining ears, the show struggles to gain momentum - it's a bit like trying to share a joke with a deaf uncle. But once things settle down, the quartet (on Wednesday's evidence at least) are rather nicely balanced.

Each has their moment - Webster exhibiting an unnerving gift for spontaneous rhyme, Mullarkey naming 18th-century British generals after building societies, and Frost belabouring Izzard with a beanbag one more time than the star of the show seems to find amusing. It's certainly the man with the metallic blue trousers that everyone has come to see, but any fears that Eddie's ego had expanded to such an extent that there would be no room on the stage for other performers prove mercifully unfounded.

In fact, Izzard is a surprisingly - and agreeably - unobtrusive presence, almost as if listening to himself do this for a month has helped him get rid of some of the self-regarding mannerisms that were beginning to make him annoying. The notorious improvisation audience has sadly made no such adjustment. Observing the foolish expression on the face of the man in front as he repeatedly shouts "underpants", it's hard to resist the conclusion that - notwithstanding the sterling efforts of Izzard and co to render it palatable - this is a form of entertainment that the government really ought to outlaw.

Seventeen - count them, 17 - nervous hopefuls took to the Hackney Empire stage last Sunday for the ritzy East London venue's New Act of the Year Final. And at the end of an extremely long but not entirely arduous evening a miracle occurred: the best man won. Jon Reed, who used to edit the Scunthorpe United fanzine, showed his star quality by projecting on to a small screen a fantastic bit of animation in which Terry Savalas comes back to life. Reed's engagingly murky streams of consciousness owe a clear debt to Vic & Bob, but given the right backing it is a debt he may well soon find himself in a position to pay back.

One Word Improv: Albery, W1 (0171 867 1115), to 16 March.