Lyric Hammersmith, W6 (0181-741 2311)
Neil Bartlett's superb RSC revival of this 1740 tragicomedy relocates Marivaux's fascinatingly heartless experiment in sex and sexuality to the fringes of a 1930s costume ball. Rising star Hayley Carmichael and a uniformly excellent cast handle the philosophical kinkiness and farcical physicality with ditzy delightfulness and exquisite cruelty, and everything ends, profoundly, in tears. This is a devilishly clever staging of a diabolically potent play.
Prince Edward Theatre, W1
It has jokes that make Are You Being Served? sound like Moliere, but unlike most K-Tel-compilation West End musicals, this Abba-hits show is almost niftily integrated. Siobhan McCarthy is excellent as the single mother contemplating her daughter's wedding, as is Jenny Galloway as her very funny friend. The choreography is woefully underdone, but there are surprising moments in Phyllida Lloyd's handsome production, which finally achieves airborne silliness.
The Colonel Bird
Gate Theatre, W11
Hristo Boytchev's elating 1997 comedy makes a timely debut in Rupert Goold's exuberant staging. A wonderful image of a mad, embattled state-within-a-state turns into a telling comedy about barmy idealism and touchingly misplaced reverence for, and faith in, the institutions of Nato and the United Nations. A madcap scheme of sending messages to European institutions by bird results in a daft yet haunting picture. Potty, and marvellously well acted.
Young Vic, SE1 (0171-928 6363)
After early signs of one-note sentimentalisation, Paul Rhys's performance catches fire when the hero begins to feign insanity. No one since Mark Rylance has transmitted so strong a sense of Hamlet's spiritual sweetness or the fundamental peace he has achieved by the time he returns from England. The strong thread of his performance compensates for some interpretative niggles in a basically very intelligent production from a talented company.