The play I have just seen is not the play you will see. Of course, one of the draws of live performance is that no two nights are the same, but that idea is taken to a mesmerising extreme in Tim Crouch’s An Oak Tree, celebrating its 10^th anniversary. Every night, a new guest actor – who has never seen the show nor read the script – joins Crouch in this two-hander; past playmates include Sophie Okonedo, Christopher Eccleston, Frances McDormand and Roger Lloyd Pack.

Can we really distinguish between experience-based judgement and personal bias? Caroline, the social worker at the centre of American writer Rebecca Gilman’s latest "issue" play, trusts a gut instinct informed by her 25-year career, but those decisions – which shape the lives of her young charges and their families – are gradually revealed to be subjective in the extreme. The passion that fuels her commitment to an arduous, under-appreciated job is also the reason she might not be suitable to perform it.

The play that lost the 2011 Tony Award to War Horse is now receiving its British debut at the very address where War Horse premiered. But such theatrical coincidences won't register in most circles as much as a title, The Motherf**ker with the Hat, that sent newspaper copy desks into a tailspin (the New York Times didn't print the M word at all, even with the asterisks). Such hoo-ha, one feels, makes a certain kind of sense given the perpetual tailspin in which the characters in Stephen Adly Guirgis's high-octane theatrical universe exist.

One of the most talented playwrights to emerge in the 2000s, debbie tucker green is a law unto herself. The best word to describe her is uncompromising. When I interviewed her in 2003 she refused pointblank to answer any questions about her West Indian background and since then she has steadfastly declined to discuss her work in the media. Like Caryl Churchill, she doesn’t do publicity. So that just leaves the work, which is always provocative, original and written in an unmistakable voice.

“We’re completely pro sex.” Rashdash, who collaborated with Alice Birch on this anarchic challenge to pornography, are not objecting on prudish grounds – their concern is the corrosive impact of degrading, dehumanising material. We are all affected, and we all need to seek a solution.

Seldom has there been such impassioned debate about whether a play has a right to exist. Writer Jonathan Maitland faced a barrage of criticism, with many accusing him of exploitation; others felt it was too soon for freshly unveiled horror to re-emerge on stage. Lead actor Alistair McGowan disagreed, noting Savile’s victims feel the telling of this tale comes “30 years too late”.

Football is a subject close to Patrick Marber's heart. He's a lifelong Arsenal fan and during his sojourn away from London (and writing, as he was suffering from writer's block for much of it) in Sussex, he became involved with his local non-league team, Lewes, helping to establish it as a community-owned club in 2010.

Titles can be warnings as well as come-ons. In Gary Owen’s new play about a teenager growing up in the Welsh Valleys, it’s not difficult to guess what the main theme of the play is. Stumbling out of the performance tonight I had the distinct impression that this is the most disturbing, even chilling, play of the year. Not only is it written with enormous skill, but what it has to say about men, and boys, feels both emotionally true and morally repellant. It’s a drama about truths that maybe I just don’t want to know about.

In a peculiarly Beckettian development, the creative team of this Sydney Theatre Company production spent several weeks of rehearsal waiting not for Godot, but for their director. Tamás Ascher – who spotted the casting potential of Uncle Vanya co-stars Hugo Weaving and Richard Roxburgh for the 1953 absurdist classic in which nothing happens, twice – was eventually forced to withdraw, leaving company director Andrew Upton to work within the set already developed by Ascher and designer Zsolt Khell.

Few cities have been so central to the European imagination as Berlin in the 20th century. At the centre of imperial power, then of Weimar, next the hub of Nazi Germany, then for some 50 years a symbol of a divided Cold War world. In Rose Lewenstein’s new play, Now This Is Not the End, the city is remembered with a touch of nostalgia by Eva, an old German lady living in London. But these memories are under threat: she is beginning to suffer from dementia so her vivid recollections are becoming cloudy – can anyone help her preserve her past?