I'm planning to write the second novel in my YA Sci-Fi series: Zack Jackson & The Cytherian Academy. I might change my mind at the last minute and work on my next fantasy novel instead, but my brain is in Sci-Fi mode, so I should take advantage of it. I have a general plot already, though. Earth Kid (43rd century), first time away at school on a different planet, dealing with more aliens, kids who don't think he should be there, etc. I might even throw something about bullying in there, though I thought about doing it without a villain, per se, but I think that might be difficult.

Plus, writing a 50K - 75K YA Novel in 30 days is slightly easier than a 100K+ fantasy novel, even if I am already 13K words into it.

I've had pretty good luck with NaNoWriMo. 2008 was the only year in which I was unable to write 50K words, but my wife died on 11/11, so I have a good excuse. Once Zack Jackson & The Cult of Athos gets published (hopefully before Christmas), that'll make two NaNos published for me, out of three books (it's time consuming 'cause I'm doing it right: hiring editors, cover artists, finding Beta Readers for feedback, etc.).