2345. “Puck One” by Elvis Costello
Also available at the whole album link.
Keeping in mind that this is essentially classical dance music, “Puck One” establishes a great (almost “Middle Eastern”) feel for Puck, a major fairy in this story. There’s also a touch of Russian music in there if I’m not very much mistaken.
Puck is traditionally used as a framing device for the play, so it’s appropriate that he’d be present before the first act even starts.