It was pitch dark and I was holding a playing card, wandering through a black maze to a bar to get into “the experience.” That’s how Sleep No More began, an immersive site-specific theater piece open now in New York City, based on Shakespeare’s Macbeth and Alfred Hitchcock’s Rebecca. I had “checked in” to the McKittrick hotel, a couple of warehouses that had been converted into five floors of rooms the audience was free to wander.