Cool Christmas events keep popping up. Now it’s a special two-hour Christmas edition of “Theme Time Radio Hour,” Bob Dylan’s weekly broadcast on satellite radio station XM, highlighted by a recitation of “Twas the Night Before Christmas” from His Bobness. The idea of Mr. Tambourine Man wheezing and growling the names of Santa’s reindeer sounds like a joke that wandered in from A Prairie Home Companion, but I have to admit I’m intrigued.