The best playwrights have an antenna-like ability to pick up, and respond to, the new conflicts and fault lines that appear in society. Over the past five or so years, the antagonism between the baby-boomer generation, who are now parents with everything, and their kids, who have nothing but debts, has increasingly intensified. And no play articulates this conflict better than Mike Bartlett’s latest, which opened last night, in a production starring Victoria Hamilton and Claire Foy.

There is nothing quite so exciting as witnessing the debut of a fresh new voice. But young writers can be rather frail creatures, and their exposure in the high-profile Royal Court Young Writers Festival might sometimes highlight their failings as much as their virtues. In actor Hayley Squires’s first play, which opened last night, there is plenty of evidence of a fiery new talent coming into the world, but also some doubt about the writer’s ability to mould her insights into a compelling story.

Playwright Martin Crimp is one of British theatre’s best-kept secrets. Although his neon-lit name appears in the theatre capitals of Europe, with his work a big hit at festivals all over the continent, here he is better known to students - who love his 1997 masterpiece Attempts on Her Life - than to ordinary theatregoers. The crowds that saw the 2009 West End revival of his present-day version of Molière’s The Misanthrope will remember how Keira Knightley and Damian Lewis spoke the witty text, but would they now recall who wrote it?

The Royal Court has been finding and developing young writers for four decades. Its Young Writers Festival has helped launch the careers of a variety of talents such as Simon Stephens (winner of the 2005 Olivier for Best Newcomer), Christopher Shinn (nominated for the 2008 Pulitzer Prize), Bola Agbaje (winner of an Olivier in 2008), as well as Michael Wynne, Chloe Moss and Alia Bano. This year, along with a full programme of readings, short plays, workshops and talks, it hosts two full-length plays. The first, which opened last night, is actor Luke Norris’s London debut.

Is there a more evocative location than Essex? In his 2000 play Under the Blue Sky, one of David Eldridge’s characters shouts the unforgettable words: “I’m from Essex and I’m dancing!” Now back at this venue for the first time since that play, Eldridge proves that he is much more than the common characterisation of him as “the writer as bloke”. But can his new play, which opened last night and is set in his favourite county, dance as well as his previous ones?

Can you replace a wife with a doctrine? Under normal circumstances, the question would be absurd, but given that Joe Penhall’s new play, which opened last night, is the latest of a crop that have explored belief, spirituality and religion, the conundrum is a very real one. And it’s here presented with unforgettable force in a compelling and stimulating play which itself seems guaranteed to haunt you.

At the newly renamed Harold Pinter Theatre (formerly the Comedy), the inaugural show is a special tribute to the Nobel Prize-winning playwright, who died in 2008. The subject matter of Ariel Dorfman’s play, which won an Olivier Award on its first outing in 1991, is a powerful reminder that Pinter was a human rights activist. He was also a friend of Dorfman so this revival, which stars Thandie Newton and opened last night, is an inspired choice of production.

“Why does anyone ever have kids?” By the time a character in April De Angelis’s new comedy utters this exasperated exclamation, there are many in the audience - whether parents or children, or both - who must have had the same thought. And more than once in the evening. For this exceptionally hilarious and perceptive play, which opened last night, not only tickles the insides of your arm, but also lights up the senses and then gives you a quick cuddle, too.

“Go home. This is not your business. This is not your war.” So a Congolese warlord tells Sadhbh, an Irish human-rights defender, in Stella Feehily’s new drama for Out of Joint. Has the arrogance and exploitation of colonialism been replaced by the interference of aid organisations? Are the motives of those drawn to troubled countries purely altruistic? And what real hope have they of making a difference, after the media has lost interest in a conflict and left?

Can an ordinary wooden chair be an instrument of torture? Of course, every brute investigation makes use of such furniture, whether as a place to tie the victim down, or as a weapon to attack them with. But, as Debbie Tucker Green’s new play so eloquently shows, the wooden chair can also be a more subtle and unexpected instrument of fraught emotion: at every meeting of a truth and reconciliation commission, the wooden chair is there in the hall, itself a dumb witness to the clash of old enemies.