THE RSC must be kicking itself. While it's doing Tennessee Williams, Samuel Beckett and Stephen Poliakoff, an American group has come up with a neat spin on the RSC's resident playwright. The Acting Company has commissioned and produced seven plays by American playwrights inspired by Shakespeare's sonnets. Three of the writers are Pulitzer Prize-winners (Tony Kushner, Wendy Wasserstein and Marsha Norman) and there are pieces, too, by Eric Bogosian, who wrote Talk Radio, and John Guare, who wrote Six Degrees of Separation. These peppy, off-beat playlets work very well together. Cheekily enough, the excellent Acting Company performs them, as part of the "Inventing America" season at the Barbican, in a venue the RSC has temporarily vacated, the Pit.

Love's Fire sounds grand and romantic, but in the hands of these writers we find ourselves returning again and again to territory staked out by Woody Allen, Stephen Sondheim and Neil Simon. Time and its destructive power, a central theme of the early sonnets, doesn't feature here. Love's Fire describes an Elizabethan equivalent of what Manhattanites would call "problems with relationships".

Characters want what they can't have, don't want what they've got, or want someone who wants someone else. We get anguish, anxiety, ambivalence, transference, neuroses and not-knowing. It's as if the authors have each taken their 14 lines and spread them out on the analyst's couch.

In Bogosian's broad comedy, a fiancee takes a Hell's Angel as a lover as an antidote to her nice prospective husband ("being full of your ne'er cloying sweetness/ To bitter sauces did I frame my feeding"). In Waiting for Philip Glass, Wasserstein gives us savage social comedy at a bitchy East Hampton drinks party held in honour of the composer ("lilies that fester smell far worse than weeds"). In Sonnet 140, Marsha Norman sets up her own La Ronde with a series of betrayals where there's always someone trying to hang on to a comforting fiction ("better it were,/ Though not to love, yet, love, to tell me so"). Kushner's massively titled Terminating, or Lass Meine Schmerzen Nicht Verloren Sein, or Ambivalence is a sublimely crazy view of the mental acrobatics of New York sophisticates: it takes off, wittily, from the dilemma of alternating between feasting and starving in Sonnet 75's "So are you to my thoughts as food to life ... ". These pieces return us to the Sonnets in a far more illuminating and entertaining way than scholars' footnotes. Having seen seven sonnets, you want to see seven more. And seven by British writers. They would be comically different.

At the end of The Bowler Hat, Marcel Marceau and his company take a curtain call; then he takes a solo bow. The applause continues and Marceau waits for the company to come on and take another bow. They're a little slow. His elderly white face turns upstage and gives this sudden, ferocious glare into the wings and the company run on pretty damn fast.

It's the only time you see emotion in Marceau's eyes. One of his talents is to shut out the expressiveness of the eyes and let us read emotions through gesture and movement. The glare also says everything we've already guessed about Marceau's relationship with his company. He is the teacher. They are the pupils.

The trouble is, he is also - in artistic terms - a giant. The Bowler Hat, an old-fashioned sentimental story about a Treasury clerk who wants to trade in his bowler for a wide-brimmed Valentino, looks as if it's been devised to provide roles for his company. When Marceau mimes lighting a cigar, his fingers fluttering with the flame of the match, or mimes leaning against a mantelpiece, or mimes with a flourish of his wrist, turning a sword in the air and sheaving it in a scabbard, we see glimpses of his genius. But no one else in the company comes near this level of stillness and precision. If only Marceau would do a contemporary, unsentimental subject or play a character his own age. It could be harrowing.

At the Victoria Palace, there's a very average revival of Sweet Charity. This Sixties musical, directed by Carol Metcalfe, suffers from a cloyingly dated and contrived book by Neil Simon (based on a Fellini script). The show does boast great numbers ("Hey Big Spender", "The Rhythm of Life", etc), but the steps, originally choreographed by Bob Fosse, now look heartless and puppet-like in Chet Walker's recreation. Bonnie Langford plays Charity as a likeable trouper, chewing gum, hitching up her skimpy dress and wiggling her blonde head. She's too wholesome for the role: her seaside-postcard cheekiness would suit a Carry On film.

Nabokov's Gloves, the latest play from Peter Moffat, an ex-barrister, deals with a married lawyer falling in love with a client, with disastrous consequences. It shows how tricky it can be for youngish modern actors to play youngish modern lawyers. The mental processes are entirely different. These barristers are all talk - self-aware, articulate, callous. Whereas actors are always looking for the subtext. Here, Ian Brown's cast make heavy weather of the brittle dialogue, which veers between the overwritten ("the spin-dryer that is your lawyer's soul") and the strident ('I win cases because I've got enormous tits"). Nabokov's Gloves ends up achieving the opposite effect to that of a swan: paddling furiously on the surface with nothing happening at a deeper level. Greg Wise is miscast as the lawyer. As his wife, the uneasy Niamh Cusack looks as if she wants to sack her agent for getting her into this callow piece. The zestful David Cardy looks most at home, as the champagne-swigging clerk complaining that the gazpacho is cold.

'Love's Fire': Pit, EC2 (0171 638 8891), to 6 Jun. 'Bowler Hat': Old Vic, SE1 (0171 928 7616), to 5 Jun. 'Charity': Victoria Palace, SW1 (0171 834 1371). 'Gloves': Hampstead, NW3 (0171 722 9301), to 20 Jun.