From what I've seen, there's usually some sort of Christmas-themed series of posts in December -- LOLs and things like that. Last years involved advent_tree, and I've heard of a Doctor Elf. I also vaguely remember a plot to save Santa from looking through the archives. However, as the person admitted themselves in advent_tree, these events tend to peter out. (The tree one, for example, only lasted about a week or so. Doc and company participated in a scavenger hunt to get presents, and never actually got replies when it came to actually RECEIVING the gifts. I didn't think it worth it to try and poke). It looks like there's not going to be one this year -- or, if there is, it's delayed. *shrug*