I've already signed up for National Novel Writing Month, but I also just found out about this ongoing challenge from writer/illustrator Debbie Ohi: http://inkygirl.com/inkygirl-wordcount-challenge/ 
Ohi's challenge encourages people to write six days a week and set a lower word-count goal for a realistic attempt at regular writing. Goals can be bumped up or down as needed.
I'll give it a shot doing both since I intend on a 250-word goal for the year-round challenge and would meet that if I manage the NaNo goal (1,667 words per day for a month) but I'm thinking NaNo isn't as realistic for getting me to write regularly!
If we have any writers on the board, let me know if you're doing either challenge or need a writing support buddy throughout the year. :) You can PM me if you're shy, I won't mind. :)