To look at the current crop of new plays, you'd think that all twentysomethings are interested in is Britpop and beer. But then again, what else are young playwrights to write about except their own inexperience?
"Something's got to be said, and I don't know if we've got anything to say," says a young woman, cradling a can of beer, surveying her audience meaningfully. In its posturing lack of assertion, this anti-statement - from Zero, by Frantic Assembly - could serve as the creed of a bizarre new dramatic sub-genre: the twentysomething play.

Plays written by twentysomethings, particularly male twentysomethings, have been rife for a while. But many of the so-called "bratpack" credited with rejuvenating theatre over the past few years precociously located their imaginations beyond the immediate concerns of their peer group. Martin McDonagh, for example, headed for fantasy Ireland in The Leenane Trilogy, Jez Butterworth for a reconfigured Fifties Soho in Mojo. When 31-year-old Mark Ravenhill (above) marched on to home soil with Shopping and Fucking last year, it looked as though the definitive stage answer to television's This Life had been written in one fell swoop; henceforward it would be hard to convey the experiences of the in-flux generation, struggling with their precarious Nineties lives, without a sense of deja vu, of uninspired sameness. (Aptly, Ravenhill himself has now been commandeered to breathe angst into This Life's third series).

Yet the prosaic and the repetitive, the stressed-out as much as the sexed- up, are the flaunted hallmarks of the current crop of plays about men and women barely old enough to remember the last Labour government. Even more than Shopping and Fucking, these co-devised pieces confine themselves to the here and now, conjuring a physically urgent sense of an age group whose time is almost audibly ticking away.

Frantic Assembly's Zero is TV's Friends without the jokes. Or the character details. It does, though, have cans of beer, which the cast throw to one another, in a chummy way, in between rushing around to screeching techno music and earnestly addressing the audience like new-found best buddies. Instead of a Manhattan apartment, they have a large, plastic doll's house. Apparently conceived "in the back of a minibus approaching the equator in Ecuador", Zero's theme is the millennium. The tone alternates between the portentous - "We are children of chaos, children of the damned" - and the hyper-confessional - "I can see I'm really boring the tits off you".

John Keates's 27, performed by his theatre company Fecund, involves a similar act of navel-gazing to bursts of Britpop and club anthems. The title marks the age at which Keates became conscious of time galloping, and provides the cue for a multi-media retrospective/celebration of his life to date: birth, school, teen crushes, university, trips to Ibiza, first shite job, London hedonism etc. He (or, at least, the actor playing him) becomes a kind of everybloke, on a journey of self-realisation, his conclusion: "What's wrong with failure? Glorious failure?"

Keates wouldn't exactly be an ideal suitor for Grace, the quaintly named heroine of Sarah Woods's play of the same name, who has not a gram of the chemical generation in her. Her days are spent sorting through the options that force their way through umpteen hatch-doors in her bedroom walls as her biological alarm-clock hits 30. Her opening "memo to self", in which she makes a note to do everything from get married to swim the Channel, suggests that she could be the younger, more surreal sister of Bridget Jones. Like Ms Jones, her refrain is one of jocular exasperation - she is too panicked to have anything insightful to say.

It would be convenient to dismiss these plays as under-achieving, self- indulgent, creatively bankrupt attempts to cash in on youth culture, their truisms fit only for people with zero taste. You're in your twenties? You got nothing particular to say? Don't worry - throw on some jeans and a T-shirt, and let's do the show right here! Except that critics and audiences alike have fallen for them in a big way. Particularly Grace, still on tour after a year. As Victoria Worsley, who plays the image of her former "disastrously single" self, points out, "Grace is about recognition, not revelation. Some guys ask, `What's it about?' It is ordinary, but that's the point. It doesn't feel ordinary when you are going through it; it feels very painful."

"From the perspective of a traditional playwright, 27 is a bad play," John Keates admits, "but there is something happening, which it is difficult to define. The intention is create emotional temperatures that, in an accumulative way, have an impact on the audience."

Director's guff, you might think, but, despite its patchy script, 27 is a surprisingly moving representation of a constantly changing period of development; like the other two works, its content is imaginatively bound up in its form.

Dramatised statements of the obvious, then, but why shouldn't theatre perform this rather modest descriptive role from time to time, in its search for new audiences and new relevance? The only danger is, of course, that every young company will start feeding on its own inexperience; we'll be dragged into a youth ghetto and bludgeoned with mortgage crises and premarital hang-ups. We'll just have to learn to spot pale imitations of This Life: a few months ago it was Daragh Carville's Language Roulette, guys and gals quick-firing Seventies TV references at each other in a pub. At the moment, it's Matt Markham's Questing in Hampstead, which opens with the immortal line: "Imagine what life will be like when the last can of beer has been opened."

That's one generational gambit this particular lager-swilling 27-year- old finds impossible to swallow.

`Questing': to Sunday, Pentameters Theatre, London NW3 (0171 435 3648)

`Zero': 13-15 October, BAC, London SW11 (0171-223 2223)

`Grace': 18-19 October, BAC (as above)

`27': 27 November-14 December, Oval House, London SW11 (0171-582 7680) and touring