Yes and no... I mean some people do it, but it's not like everyone does it. Christmas is definitely the time to do it though, if you're going to build one. There are a lot of kits out there, but I find them to be of lackluster quality. Building your own house from scratch takes the cake every time for sure.
I know that it's become something I usually do every year now, though it's not always a house, just something cool. Last year we did a gingerbread German WW2 Panzer tank with a motor inside and a movable turret, it was also quite cool.
This house is by far the largest gingerbread anything I've ever been a part of, and it turned out fantastically.
We modeled it after this house I found online:
Jeff