Our school's demo teams perform during Thanksgiving and Christmas parades. I don't think I've seen holiday specials in particular though we do advertise in town circulars, and a community health magazine that is available in doctor's offices and hospitals. I think we always offer a month special that includes a dobok.
I think a holiday special is a great idea. It would make a great Christmas gift for someone wanting to get in shape starting January. And a lot of people might be inclined to hit the dojang instead of a gym.