The Fiasco Theatre Company's six-person "Cymbeline" at the Barrow Street Theater is a romp! The talented young actors sing and play music, too - Tallis, bluegrass, why not? "Cymbeline" is a capriccio, its plot as carefully contrived as an old-fashioned detective novel, so playing up the joyful artifice of it by doubling up characters makes it work all the better. Through its canny contrivances it makes you both want to be the pawn of a playful providence - where nothing is as it seems and everything works out in the end - and then, perhaps, not.