A little over a year ago I stumbled across a video on YouTube of a men's a cappella group from Indiana University called Stright No Chaser. They performed 12 Days of Christmas and I shared it with everyone I could for a few months, then forgot about it.
Evidently that same virus went viral. The group created a Christmas album, has a website, and has just released an EP (and of course you can be a Facebook fan too).
I doesn't hurt that they enjoy a bit of humor as well.