Intensity and intimacy are the defining qualities of Richard Eyre's triumphant production of King Lear at the National Theatre is a triumph of an actor
Stage fright kept Ian Holm away from the theatre for years. His achievement last week as King Lear somehow adds, retrospectively, to that loss. It is a magnificent performance, charting a path through rage, insight and regret with graphic precision. This short, compact, peremptory figure strides in, kisses his youngest daughter Cordelia on the head, pats the table and sets about dividing up the kingdom. The family conference is a little hoop he wants each of them to jump through. Quite why Cordelia doesn't jump is curious. She takes the view - indeed, she seems to arrive at it quite suddenly - that she loves her Dad according to his bond (no more, no less). Once that position is taken, everything goes horribly wrong. As Michael Ignatieff notes in the programme to the National's new Lear, this is one of those mad family rows that need never have happened.

Holm's Lear is aggressive. He bangs the table with his ivory-handled whip, and then, when he perceives the mistake is of his own making ("Lear! Lear! Lear!") bangs it with his forehead. But the lashes are mild stuff compared to the abuse he dishes out: Holm is piercingly cruel to his daughters. He struts round the traverse stage like an old huntsman. Then he fixes his eyes on the middle distance, his head twitching, as he realises he did Cordelia "wrong". Each slight to his status catches him on the blindside. He turns from one ungrateful daughter to the other, his hand cupped disbelievingly to his ear. Madness looms as a daunting possibility: he speaks of it in a level, sincere way ("Do not make me mad"). As it unseats him, bit by bit, Holm paws at his cropped hair, tugs at the beard and chokes on words.

In Richard Eyre's powerfully cogent production we see just what the Lear family is up against. Dad is not easy. The elder sisters, the smartly coiffured Goneril (Barbara Flynn) and Regan (Amanda Redman), are quite right. He is "full of changes". Redman speaks plainly, telling him to his face: "You are old." Later, she won't allow him to stay because "this house is little". Budgets being what they are at the National, we only get to see six mud-splattered knights and squires, sprawling round the table with saddles and bridles, rather than the famed 100 that follow Lear. Spare a thought for Regan: you wouldn't want another 94 of them staying at your place.

In the studio-sized Cottesloe, we get a close, domestic Lear. The audience sits on three sides, bringing the intensity of an arena to these rapidly unfolding antagonisms. The intimacy is important and so is the width. We are in the middle and our sympathies flick back and forth. Eyre's uncluttered approach immediately points up how neatly the Gloucester sub-plot parallels Lear's. Timothy West's courtly Gloucester is having a particularly trying day at work. West nicely combines patrician authority with Whitehall deference. His bastard son Edmund (Finbar Lynch) has no problem turning this trusting politician against his other son, the nervously bookish Edgar (Paul Rhys). Iago-like, Lynch controls the early scenes, confiding his plans to us in lively asides that turn the stage into his personal platform.

When Holm heads out into the storm, the orange walls that stand at either end of Bob Crowley's set tip forward to reveal rain pouring down a black sheet: a spectacular moment that provides its own chilly draught. By the time Holm meets Rhys, disguised as Poor Tom, in the temporary asylum of the hovel, his freefall descent has bottomed out. Rhys has a wide, nervous smile that constantly suggests pain rather than pleasure. These two naked figures cling like lost souls. In Rhys's entrancing performance, Edgar emerges as a pivotal figure. After the blinding of Gloucester, Eyre cuts the servants' comforting lines. It is Rhys who must apply the balm, taking his father to the edge of Dover Cliffs.

With few props and set changes, the scenes spring suddenly to life: David Burke's impressively pugnacious Kent wakes a whole household with his night-time taunting of William Osborne's lugubrious Oswald. Like so many characters in this Lear, Burke's Kent has his own absorbing trajectory. Everyone goes through some storm. Michael Bryant's elderly, jaunty, motley- clad Fool looks finally as if he too has had the light extinguished. While in Holm's last scenes, the strut gives way to stuttering steps, the glare to feeble squints, and throaty growls to whispers of grim resilience. It's a major Shakespearean performance.

It's a tough choice, whether to go to a French restaurant or a Chinese one, but in Hurlyburly by David Rabe, Darlene (Elizabeth McGovern) tells Eddie (Rupert Graves) she doesn't care, he can decide for himself. Eddie isn't satisfied: he wants to know which she'd prefer. This small dispute, following as it does so soon after Darlene's admission that she once had an abortion, builds into a ferociously funny argument, in which Eddie says Darlene's mind must be a complete mental fog because French and Chinese are entirely different and Darlene says they aren't: "Not in my inner emotional subjective experience of them!"

Rabe's 1984 play, a welcome British premiere by the Peter Hall Company, is set in a Hollywood house occupied by those on the fringes of the movie business. When they're not snorting coke, flicking through scripts, or getting ready for some meeting, this self-absorbed bunch keep grasping after what they feel about things. It's slippery stuff. As Darlene says about restaurants, "I can't be that specific about my feelings." Talk frequently precedes thought ("blah, blah, blah," they go) and Rabe tracks in glorious detail the Byzantine mental processes, the riffs and arias that bubble through the minds of this clever, amoral crowd. Here are people who behave like kids while having kids of their own. Hurlyburly requires conducting as much as directing. Wilson Milam draws good performances: of the men, Andy Serkis and Stephen Dillane catch the idiom best. The Old Vic isn't the right venue, but Rabe's dialogue is a real treat. It's so American you wish you'd seen William Hurt, Harvey Keitel and Christopher Walken in the original. As it is, this is the next best thing.

At the Lyric Hammersmith, artistic director Neil Bartlett revives the theatre's revue tradition with new sketches from Richard Curtis, Harold Pinter, Stephen Fry and someone very funny called Anon. In Then Again ... Bartlett links up with the past through the casting of the inspired Sheila Hancock (in revue here in 1959), who is joined by Dawn French, Desmond Barrit, Neil Mullarkey and pianist John Gould. It's a big, varied evening, with 30 sketches. The best have a formal silliness: Dawn French joins Mullarkey to do an impro (idea by Richard Curtis), with suggestions from the audience, but she keeps bringing the impro back to something she's prepared earlier. In "Prompt" (Curtis again), the confessions have been scripted in advance, but they keep forgetting the words. In the last hilarious sketch (by Anon) a memorial address is subverted by the subject's obscene nickname.

After his disappointing Week With Tony, the young playwright David Eldridge returns, with Summer Begins, to the territory of his impressive debut, Serving It Up. Eldridge's third play, part of the Donmar's "Four Corners" season, follows two sisters in Barking, east London. Both Keanu Reeves fans, one of them is getting together with a guy and the other is about to dump a guy. These are dangerously slight dramatic premises to sustain an entire play (viz, "Have you shagged him?"). But whenever Eldridge catches hold of something frank and surprising from this young-adult world of "slappers", "shit-for-brains" and "bollocks ideas", he is, in own way, "dead smart".

'Lear': RNT, SE1 (0171 928 2252); 'Hurlyburly': Old Vic, SE1 (0171 928 7616); 'Then Again': Lyric,W6 (0181 741 2311); "Summer Begins": Donmar, WC2 (0171 369 1732).