Before the NFL got their hands on Dire Straits' "The Walk of Life," I recall that the original video was about a subway Busker. What's a Busker? A "Street performer," giving a public concert for coins, bills, or, occasionally applause as well as money. Mary Chapin Carpenter takes us with her on a rainy Winter session, amid the lights and bustle of Christmas. Be nice to your local Busker, "American Idol" isn't looking for them, in spite of their talent.