Another show I managed to see is Constellation, a show about relationships as seen through the eyes of different worldviews of physics. It's explained in my review in more details. It's a bit of a weepie but nice and short and pretty great.
I also saw, for free courtesy of the Almeida's blogger's program, a play about Robert Frost and, er, an English war poet. It was meh - good on poetry but not an enthralling play.