The playwright of the moment in the American theatre is 32-year-old Sarah Ruhl, whose award-winning, much-buzzed-about play, “The Clean House,” is at last hitting New York; whose lower-profile drama, “Eurydice,” earned a near-benediction from The New York Times a few weeks ago; and — oh, the other thing — who made her way onto the genius list when she became a MacArthur Fellow last month. “The superstitious part of me goes, ‘Uh-oh, when is the other shoe going to drop?’ ” she said. “There is so much happening at once. But the nonsuperstitious part of me is trying to enjoy it and see it as the result of 10 years of labor.”