Once upon a time, there was a radio program trapped in the tall tower of a stone building. . . Studio 360 falls under the spell of fairy tales. Kurt Andersen and Gregory Maguire, who wrote Wicked, talk about why at Christmas, America turns into “Nutcracker Nation.” They hear about Haroun and the Sea of Stories, Salman Rushdie’s tale about a boy who sets out to save his village from an evil wizard. And Tonya Pinkins, star of the musical Caroline, Or Change, reads the classic tale Rumpelstiltskin.