I heard about this last night.
http://www.nanowrimo.org/eng/hownanoworks It's as easy as it sounds. You sign up in October, the contest starts Nov 1, and you have until Nov 31 to write a 50K word novel. The only prize is bragging rights.
This is a really bad November to do it, but it's something I'd like to attempt next year. I have pretty good luck with autobiographical fiction, but other than that, I'm not much for ideas. I'd have to crib ideas from various sources, and I'm sure that's frowned upon. I haven't had an original thought in years and years, certainly not one substantial enough to write 50,000 words about.