The two WASPish couples at the center of Sarah Ruhl’s sexy/bonkers magical realist tragicomedy How to Transcend a Happy Marriage could have walked in from any number of other American plays. You know the type: they read The Atlantic, wear Joy Division T-shirts un-ironically, start each new year by reading a play, and fall over themselves to avoid the appearance of political incorrectness. Their living rooms are the familiar battlegrounds of bourgeois drama from Akhtar to Zola. The bloody goat carcass suspended over David Zinn’s set, though, makes it clear that we’re in the Ruhl-iverse, and little about the next two hours will be business-as-usual.