I'm participating in my first NaNoWriMo. EXCITEMENT!
It's a good motivator for me to get in the middle of the novel that's been in my head for like, 10 years or so, and actually commit it to words rather than have it languish in the ether of my brain.
The funny thing is, when I sat down and began writing, I started at a point I had never even thought of. So it's as much a journey of discovery as it is one of labor :)