Fuerzabruta, Roundhouse, London <br/> Sit And Shiver, New End Theatre, London

After a two-year closure and a £30m refurbishment, the Roundhouse is back in business as a handsomely equipped arts centre. It is marking the occasion with the ultimate in wild reopening parties. Fuerzabruta ("Brute Force") is the creation of a splinter group from the Argentinian company De La Guarda, which gave the venue one of its biggest hits with Villa Villa in 1999.

Directed by Diqui James, the new show combines astounding aerobatics with ravishing imagery and an atmosphere that owes more to clubbing than to sedate theatre-going. Underscored by heavy trance music, the attractions thrust their way into the dense, milling throng of punters assembled in the cavernous, infernally lit space.

The event begins with the spectacle of a desperate man running for his life on a speeding treadmill. As brick walls and closed doors hurtle towards him, he simply smashes through them. Even when he's gunned down, his chest spurting with blood, he picks himself up, sheds one layer of a series of identical shirts, and battles on.

It's ironic that, in a show that communicates with the audience so directly and viscerally, many of the images involve people vainly struggling to make contact. In a suspended, tank-like bed, a drenched woman thrashes sleepily, while, on the underside, her lover presses against the perspex pane that separates them and tries to gain solace by mirroring her movements. Later, the couple reappear, clinging like shipwrecked survivors to the sides of a huge, storm-tossed, silver sail that resembles a great, bucking sheet of tin foil and gradually collapses as hope expires.

"When you touch the scenography, please do it softly, with the palm of your hands": it's not every show that needs to make such an announcement. Here, though, there's an extraordinary sequence where a vast plastic pool descends over the audience's heads and we see playful water nymphs leaping and splashing in the surf. The maidens peer down at us, as if we are the exotic curiosities. Eventually, this translucent membrane is so low that you can touch its pliant underside and stroke the bodies slithering above.

The company makes no claims to profundity. It's the skill, daring and technical wizardry you applaud. In such an elating airborne extravaganza, gravity is for defying.

Steven Berkoff's ebulliently comic new play, Sit and Shiver, focuses on the Jewish ritual of sitting shiva: the seven-day mourning period when loved ones sit and eulogise the deceased. As a child, Berkoff thought the phrase was "sit and shiver", which made perfect sense to him as a way of describing grief.

His autobiographical play is at once an affectionate portrait of an East End Jewish clan, whose patriarch, Monte, has died, and a criticism of the kind of neurotic tribalism that can't allow anything, least of all truth, to disturb a vision of the wholesome Yiddisher family and its noble head.

'Fuerzabruta' to 30 July (0870 389 1846; www1.roundhouse.org.uk); 'Sit and Shiver' to 2 July (0870 033 2733; www.newendtheatre.co.uk)