NBC.com has posted two more exclusive sneak peeks at the all-new Muppet Christmas special "A Muppets Christmas: Letters to Santa". The hour-long television special is set to air on NBC on December 17, 2008 at 8:00pm. The Muppets will deliver an all new one-hour special filled with song and dance, mayhem and heaps of holiday high spirits. Check out the new clips (a new four-minute preview, and a set of exclusive behind the scenes interviews with the Muppets) below or by clicking here. And you can view two additional "Letters to Santa" videos right here.