NaNoWriMo (National Novel Writing Month) is next month, November.
I've participated in it a few times before (if you count feeble one week efforts) but finished only once. And that once was just the word count. The story wasn't/still isn't done. :p
50k words/30 days... if I do it, I probably won't be able to do anything else - make avis, write fanfics, sleep. But then again it might be the only way to make myself work on that original story I started working on (and have like 5 tiny paragraphs of so far :p) Decisions, decisions...