phantagrae

Sounds like fun!

On LiveJournal, in the TXF fandom, they have often done a Secret Santa project.
One person, or a "committee" has to kind of honcho it.

The way they did it was that people would submit a post as to what they'd like from Santa--a video, some kind of fan art, like icons or whatever, or a fic.
And then they'd also sign up for whatever they're capable of providing, like writing fics or making videos, etc.

And I don't know that the stories or videos have to be at all holiday-themed. I think that depends on what people ask for in their letters to Santa.

So, Sally writes her "Dear Santa" post and asks for a fic. She kind of has to define it a bit--say, a general rating, or pairing. In our case one might have to make it clear if they can't stand Shenny fics, or if they want a Shenny fic, for instance.
Or she'd say she wants a Shamy video, or a Johnny Galecki avatar or whatever.

Sally would also be able to be an "elf" and do something for someone else, like fic or videos, etc.

Then Mary signs up and says that she's really good at making avatars, or maybe she's a good fic writer, but she doesn't write Shenny, or she doesn't write smut.
And of course, Mary would also write a "Dear Santa" letter for what she wants

So then the Committee (or Honcho) would match up the Dear Santa letters with the "elves" and would email or PM each "elf" and assign them to provide a gift for the request.

Then we would have a certain date range during with to post our gifts for each other.

Does that make sense? It doesn't have to be that complicated, I guess, but it worked that way on LJ for a few years (though one year, Santa never found my chimney...)