If you're already participating, what are you doing?
I suppose I am, albeit by accident; I'll be designing a game to build and send to my PnP Secret Santa target as an extra to the things on their wishlist that I'll also be making. I did it last year, so now it's basically a tradition and I can't avoid it. ;-)
(Of course, being a Secret Santa gift I won't be disclosing anything until next year anyway!)
It'll be more like "game design fortnight" than "game design month", though - other commitments (not least continuing trying out the other entries in the recent 2013 Solitaire Design Contest!) will keep me more or less occupied until next weekend.