It's a Scandinavian format (created by the first company to take a chance on the "Survivor" format) called "Clash of the Choirs," produced by BBC Worldwide America (the "Dancing" people):
http://www.hollywoodreporter.com/hr/conten...c12093a3f140a08"Dancing" meets "Extreme Makeover: Home Edition?"
Which means the end for now of NBC testing a game show in the week before Christmas, the first one ultimately successful ("DOND," 2005) and the second ultimately failing ("Identity," 2006). It could come back.
