TWO plays, written within a year of each other - one by Moliere (1666), one by Racine (1667) - get updated, relocated, jazzed around and tarted up in new productions. One works, one doesn't. This week it's French with or without tears.

There's a scene in Martin Crimp's new version of Moliere's The Misanthrope where Alceste, here a shabbily dressed, surly playwright, hears a scene from a draft of an unperformed play. Ken Stott's Alceste is a superbly splenetic figure, stomping round with hands dug into jacket pockets, eyes darting back and forth, grimacing and muttering blackly. For the reading he stands still. It's been written by the spruce theatre critic, Covington (a beamingly ingratiating Niall Buggy). Alceste halts Covington in disgust, wondering why "people cover page after page/ with dialogue so unplayable on the stage".

He's brave, Crimp. First he adapts Moliere. Then he satirises critics, choosing a name that neatly alludes to two of the better-known ones. Then he lectures us on what does and doesn't work on stage. Covington's play, Alceste says, is stilted, unnatural and doesn't reflect the way people speak. Huh, a theatre critic might be tempted to think: you can talk. But the thing is, Crimp and his characters can talk. Wonderfully well. Crimp sets The Misanthrope in the celebrity world of the arts and media. His verse is quick, funny and revealing. He's also cannily alert to modern idiom, to the self-aware way these people actually speak.

In The Misanthrope Crimp moves Moliere's courtly crowd into the suite of a luxury London hotel, with designer sofa and neon stand for the answerphone. Celimene becomes a 25-year-old movie star, played with gawky, disingenous charm by the film actress Elizabeth McGovern. The vain, gossipy Marquises become a successful agent and a well-connected young actor, while the pious Arsinoe becomes a jealous acting teacher, in a powdery, fussily dressed cameo from Linda Marlowe. The transformations are delightful. Lindsay Posner's glossy production draws ele- gant performances - especially from William Osborne, as Alceste's languidly reasonable friend, trying to dampen his irascible pal. Only the topical references are blurred. For reasons that are never entirely clear, Alceste has a particular dislike for David Hare.

Watching this week's other adaptation, the leadenly clever 1953, you wish the celebrated "Martian" poet Craig Raine had tried out a scene or two on the unforgiving Alceste. In his updating of Racine's Andromaque the Trojan story has been moved to 1953. Hitler has won the war, the Axis powers are in charge, and Mussolini's son, Vittorio, rules Italy. It's a love chain: Hitler's secret envoy to Rome, Count Klaus Maria von Orestes - played with Aryan sincerity by Adam Kotz - is in love with Princess Ida (Emma Fielding) who in turn is in love with the King of Italy (Jason Isaacs) or "top wop", as someone casually remarks.

The high-voltage performances, however, are determinedly upstaged by the one character who never appears: Craig Raine. Time stands still while characters guide us through his elaborate similes. Princess Ida is engaged to be married, but engaged "like a taxi". Klaus grins "like a xylophone". Hector's wife, Annette, has felt the milk moving through her breast "like something homesick for a destination". No one speaks this way; only Craig Raine writes this way.

Alceste might call this unplayable. And stilted too. Sentences stop abruptly. Then start. Again. Worst of all are the daringly explicit exchanges. Vittorio discusses Annette with his personal adviser: "The bitch. I bet she doesn't suck." "Yeah," replies the adviser. "Or swallow either." Sitting in the audience you have that embarrassing sensation teenagers get when adults try to talk dirty.

In Vicki Mortimer's set Mussolini's palace in Rome looks like the foyer of a multiplex cinema: red carpets, art deco curves, banquettes with panel lighting and a billiard table that rises out of the floor. This kitsch setting doesn't liberate the story, it constrains it. Orestes is a uniformed Waffen SS general. When he walks on, he brings so many specific historical associations the play struggles to find its own identity. "Telephone the Fuhrer now," he's told. We imagine Adolf at the other end, like someone in a BT ad. Well, it's good to talk.

That luminous, intelligent young actress Emma Fielding deliberately tries to extend her range by playing the cold, sexy Ida. But it's hard work. When she's struggling to get Vittorio back, she fails to convince us that she is the kind of demon in the bedroom who boasts that the other woman will "never piss on you the way I do". Jason Isaacs gives a very Almeida performance - precise, sensuous, preening - as Vittorio. But neither of them can save a grimly ambitious evening which keeps lapsing into a poetry reading for Martians.

In Dead White Males the Australian playwright David Williamson examines the teaching of English Literature through the credulous eyes of Angela (Claire Price), a 19-year-old student. She falls under the spell of the smooth radical lecturer, Grant Swain, very plausibly played by Jeremy Clyde, and soon views life in terms of dominant patriarchal structures, non-exploitative multiculturalism and phallocentric discourse. It's not hard to guess Williamson's own ideological bias.

To help his case, he introduces a sluggish, rustic Shakespeare (Tom Chadbon) to the present. There's no explanation - in this playful script - how Shakespeare gets here. But then, where exactly Shakespeare is coming from is one of the pertinent themes. Patrick Sandford's production attractively combines the diffuse elements - lectures, seminars, scenes from Angela's home life, and extracts from Shakespeare. Political responses keep banging up against real life. Or real life as devised by Williamson. The stingy patriarchal grandfather - the excellent John Woodvine, in cardigan and slippers - emerges, movingly, as a long-suffering saintly figure. Angela's fellow student Melissa (Lucinda Cowden), a bimbo with brains, gets a good grade by showing "signals of availability". It's too easy.

'1953': Almeida, N1 (0171 359 4404), to 30 Mar. 'The Misanthrope': Young Vic, SE1 (0171 928 6363), to 23 Mar. 'Dead White Males': Southampton Nuffield (01703 671771), to 2 Mar.