When I taught Elementary Computers, I would always try to give the kids a break near a holiday. I would allow them to play Holiday Games via my Live Binder site! Of course, if a child didn't celebrate a certain holiday they were given other options. I also didn't limit them to Christmas games at Christmas, or Halloween games at Halloween, etc. They were allowed to play any Holiday or Season related game. The kids LOVED it!
In addition to the sites on my Live Binder, here are some other sites with some great games for Christmas!