Six Dance Lessons in Six Weeks, Theatre Royal, Haymarket London<br/> The Glass Room, Hampstead Theatre, London <br/> Watership Down, Lyric Theatre, Hammersmith, London

Think Dirty Dancing without the dirt. Lily is 68 going on 72, a Baptist widow. And Michael, the instructor who turns up in a Zorro outfit to teach her the tango, is gay. So in Six Dance Lessons in Six Weeks, starring Claire Bloom and Billy Zane - an excruciatingly sentimental Broadway comedy - the only bump 'n' grind on the cards is Bloom colliding with the furniture (which occurred on press night), or the sound of your own bones under strain in the stalls as your legs yearn to bolt for the exit. I surely aged at least six years enduring this shamelessly schematic two-hander by Richard Alfieri.

Lily is lonely. Michael is lonely. Both lie about being married, both are mourning. They tick off the waltz, the foxtrot et cetera while predictably becoming buddies, having tiffs and making up ad nauseam. Zane has fine comic timing and genuine tenderness when he hugs Bloom. She remains a radiantly beautiful trouper too but, alas, her performance is stiff, her lines nervously shouted. The choreography is rudimentary. The set-changes and syrupy sunsets, under Arthur Allan Seidelman's direction, drag on as well. "You ain't seen nothing yet," croons Michael's CD player halfway through this brain-numbing bore. How true. And so it goes on.

In The Glass Room, it's not entirely clear who is leading whom a dance. That generates flickers of suspense in Ryan Craig's new ethnically and morally uneasy play about a fast-rising lawyer, Daniel Weyman's Myles, and his client, Sian Thomas's Elena. She is a swanky, beady-eyed historian who has made a media career out of being provocative and whose latest thesis - bringing David Irving to mind - is that no actual gas chambers existed in Hitler's camps. Now, under altered British law, she is to be tried for mendaciously stirring up racial hatred.

Myles' own father is Jewish: a fact he conceals from Elena. Simultaneously, he hides his involvement in the case from his dad, Fred Ridgeway's Pete, who is obsessively wary of anti-Semitism. Is Weyman's dry, pedantic Myles going to prove an ice-cold professional? Is he some kind of denier himself, shunning the culture that Pete tried to impose on him? Or is he pent-up and surreptitiously planning to destroy Elena? He could, incidentally, also find himself in a personal tangle on several fronts. His attractive flatmate, Tara, is a tabloid journalist.

It's a big shame that this isn't a better play. The Glass Room works up to its climactic speeches and plot twists about as unobtrusively as a clanking great steam engine. Myles' chess board likewise, virtually leaps up off the coffee table and yells, "Look, I'm a strategic metaphor!" Nonetheless, one cannot but applaud Craig for debating the very important, topical and tricky issues of free speech and xenophobia. Moreover, this is ethically unsettling, because Elena is initially given persuasive arguments. Anthony Clark's cast also acquit themselves commendably, especially Emma Cunniffe whose Tara is irresistibly funny when floppily drunk and Ridgeway who (having replaced Toby Salaman at short notice) is firing on all cylinders and supplies comic relief, too.

In Melly Still's scruffily beautiful and often inspired new staging of Watership Down (for those age seven and over), the rabbit-guards patrolling the totalitarian warren, Efrafa, look like Nazi storm troopers. Our heroes and heroines - Hazel, Bigwig and the other breakaway bucks and does - race around in bobble hats, woolly jumpers and sneakers. They bounce joyously on trampolines and giant-carrot pogo sticks, as if life is an adventure playground. When fighting for survival, they thrillingly spin and kick, kung fu-style, escaping cats and stoats who come screeching out of the shadows in balaclavas, brandishing flick-knives, arms whirling.

It's not as polished as Still's NT hit, Coram Boy, with some lame dialogue by adaptor Rona Munro and off-key singing. But this director-designer's productions for children are really extraordinary, reflecting their own scampering, imaginative playfulness.

k.bassett@independent.co.uk

* 'Six Dance Lessons in Six Weeks'(0870 4000 858) booking to 3 Mar; 'The Glass Room' (020 7722 9301) to 23 Dec; 'Watership Down' (0870 050 0511) to 13 Jan