WriDaNoJu - Write a Damn Novel in June (June). Goal: Write 50K in the 30 days of June. It's perfectly situated six months from November so you have optimum time to prepare for WriDaNoJu and NaNoWriMo.
I signed up a long time ago for National Novel Writing Month on nanowrimo.org and never got very far. This would be a good test to see if 30 days is a good deadline.
I think I saw that you have to write about 1500 words a day to make the 50K in a month.
There's a great bunch of stuff to do all year, too.
There's a blog event even:
NaBloPoMo - National Blog Posting Month (Year-Round). Goal: Post every day for a month.
A great organization. A huge help to writers who can be isolated.