I guess all of you have already heard about NaNoWriMo. No, don't worry, I'm not crazy enough to join ;) - I know my writing skills and that I would never ever be able to reach this goal. But there is another Community based on this.
This sounds like a lot of fun.
Running from 1. - 30. November
Write every day
Minimum commitment 100 words a day. There is no maximum, though.
You can still sign up here, but make sure that you join the community first.