With the American presidential election campaign now in full swing, the search is surely on for cultural expressions of the two nations that the candidates represent: white rich people versus the rest. Okay, maybe an exaggeration, but who says I’m unbiased? Anyway, a new play from Tarell Alvin McCraney, one of the most innovative black American playwrights of his generation, runs the risk of being seen as a metaphor for Obama’s first term in office. But does this burden the new play with too many expectations?

A powerful trend in contemporary theatre is the family play. But the families usually depicted tend to be of the standard two-point-five variety, while other more complex forms — families as they actually are — tend to be ignored. So initially the good thing about Vivienne Franzmann’s new play is that it focuses on a family where the child is adopted. More controversially, it is about a white man who adopts a black girl from Africa.

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.

When Madani Younis became the new artistic director of the Bush, some questioned his commitment to new writing, while others asked what he would bring to this small but high-profile venue. With this, his inaugural production, which opened last night, some answers suggest themselves: he’s chosen a solid new play, and he has introduced London audiences to a Lee Mattinson, a northern voice.

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?

Science rocks. In the theatre, this is a subject that offers to provide powerful experiments in metaphor. Most recently, in Nick Payne’s Constellations - and most classically in Tom Stoppard’s Arcadia, Michael Frayn’s Copenhagen and Charlotte Jones’s Humble Boy - the world of quantum mechanics, cosmology and chaos theory suggests ideas about the randomness of our daily lives. And there is nothing quite so random as love.

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.

Some plays are so weird they defy description. Well, almost. One of these must surely be the late James Saunders’s deeply absurdist play, whose first outing in 1963 launched the career of the young Michael Caine. Soon after, its author won a promising playwright award. The current revival, part of the Orange Tree’s 40th-birthday season, gives us a chance to look again at a writer whose innovative work has been consistently promoted by Sam Walters, artistic director at this address.

Spooky coincidences make good drama. Mike Bartlett’s epic follow-up to his highly successful 2010 play Earthquakes in London begins with a mind-bogglingly weird situation: every morning in the metropolis, dozens of people wake up and they’ve all had the same disturbing dream. The play, which opened last night, then goes on to examine what happens when citizens rise up to challenge the system in an era of foreign war and economic austerity.