The Power of Yes, NT Lyttelton, London<br/>The Caretaker, Everyman, Liverpool<br/>Inherit the Wind, Old Vic, London

David Hare's state-of-the-nation drama about the crash manages to entertain as it educates

David Hare's latest mission is to grapple with the financial crisis – dramatically, that is. But can his state-of-the-nation play, The Power of Yes, get to grips with such convoluted economics and be engaging into the bargain? The answer is "Yes!" On balance, at least.

Obviously, it wouldn't do to create a bubble of hype. The writer himself adopts an anxiously modest stance when he appears as a prologue. Played by the actor Anthony Calf (a Hare lookalike), the Author steps downstage, surrounded by barren darkness, and announces, "This is not a play."

"Dear me!" you may sigh. Actually, though, it's for the best. If you want to see monetary shenanigans dramatised with flair and poetic licence, Lucy Prebble's Enron is at the Royal Court and transferring to the West End, with the corporation's backers envisaged as the Three Blind Mice. By contrast, Hare's forte isn't inventiveness but, rather, factual reportage.

Here, essentially, he has spliced together trenchant and illuminating interviews with bankers and traders, financial journalists, politicians, lawyers and the supposed regulators. Some remain anonymous; some are well known, not least the hedge fund manager turned philanthropist George Soros, who's embodied by Bruce Myers with the air of a guru.

The witnesses Hare calls are outspoken, prepared to allot blame and, in some cases, criticise their own past conduct. Harvard and Myron Scholes (of the Black-Scholes formula) are principally accused of causing the rot, by claiming that elaborate mathematical equations could manage risk. Gordon Brown is scorned for stoking the boom, and for having a plaque in the Treasury devoted to the Federal Reserve Board's ex-chairman, Alan Greenspan, notorious for his sphinxlike remark, "If you think you understood me, it's because I mis-spoke." It's also encouraging to have the layperson's sense of outrage supported by a City lawyer who intimates that more bankers should, by rights, be in handcuffs – except politicians still want to cosy up to them.

Angus Jackson's production manages to be stylishly stark and fluid. A host of understated yet vibrant actors criss-cross the stage in grey suits, sharply spotlit. Corporate logos flicker on an overhead screen.

The Power of Yes has shortcomings. Its lesson-learning set-up – with a blackboard and explanation of key terms – is rather rudimentary. There are gaps: no interview with an ordinary Joe who has lost his job or home in the ongoing fallout. Sometimes elisions in the experts' intercut arguments leave you scrabbling to keep up too. Personally, however, I don't mind that this piece reaches no neat conclusion. Its polyphonic and sometimes contradictory voices are worth more than a simplistic summary.

Home ownership and repossession are, in a weirdly menacing way, crucial to The Caretaker, Pinter's modern classic from 1960. A tramp, living under the pseudonym Davies, is offered shelter by a quiet, brain-damaged oddball called Aston. The latter seems like charity personified, offering the second bed in his junk-filled bedsit. However, he has a vicious brother, Mick, who claims to be the landlord and plays malign games. They're all possibly dangerous nutters.

Christopher Morahan directs a very strong revival, with Jonathan Pryce on superb form as Davies. Scraggy and bearded – rabbiting away in his native Welsh accent – Pryce's naturalistic portrayal of mental instability is finely observed, from blithe buttock-scratching to ferocious yelling. When are we going to see his King Lear?

As well as revealing a desperate, grabbing, horribly treacherous side, Pryce's Davies is explosively funny. He and the brothers even fleetingly turn into a variety act, farcically snatching and passing his duffel bag round and round. Moreover, while Pinter's writing, in this early play, often sounds like freshly recorded real speech, Morahan simultaneously captures the hallucinatory aspects of the domestic nightmare.

Maybe Tom Brooke's cockney Mick isn't hair-raisingly convincing at every turn, but his verbal bullying, sprinkled with non sequiturs is surreally disquieting. And pairing the jutting-chinned Brooke with Peter McDonald as Aston is visually brilliant. They look unnervingly alike, and with Brooke lurking on the landing – glimpsed through a ghostly scrim – it's as if we're seeing the merciful and destructive facets of one being.

Teaching people a lesson is on the agenda again in Inherit the Wind. An instructor in an American classroom has been disseminating Darwin's theory of evolution, and the fundamentalist Christians of Tennessee are livid. This courtroom drama, written by Jerome Lawrence and Robert E Lee in 1955, was based on the hugely polemical Scopes "monkey trial" of 30 years earlier. Apparently, not a huge amount has changed. A recent survey suggested that around half the US population either reject Darwin's theory or think it's no more valid than any other.

Kevin Spacey is, manifestly, determined to take a stand against religious bigotry. And he's on storming form as the libertarian defence lawyer, Drummond. Though Spacey has startlingly aged here – with silvered hair and a stiffened spine – he exudes charisma, sardonic wit and wiliness. David Troughton is his Bible-believing, equally determined adversary, an almost grotesque pot-bellied prosecutor: guzzling, snuffling, and implicitly arrested somewhere in his personal development.

The play itself is structurally creaky, with all too obvious twists and sentimental moments (cute kids and performing monkeys). I wearied of Trevor Nunn's chorus of hymning townsfolk, forever flocking downstage, fanning themselves in the supposedly sweltering heat. Still, this revival's topicality is clear, and the sparks fly as Troughton and Spacey lock horns.

'The Power of Yes' (020-7452 3000) to 28 Oct; 'The Caretaker' (0151-709 4776) to 31 Oct; 'Inherit the Wind' (0844 871 7628) to 20 Dec