I thought about it last year, but it was the last month in my job and didn't seem right to be focused on anything else but the job and the book I was writing.
So this year I've no excuses apart from forgetfulness. But then I remembered about 3 weeks ago and signed up for
NaNoWriMo. Felt a bit faint once I'd done it (what was I thinking, writing a novel?), but hey plenty of time to think up something to write about. So I've been thinking about my plot for at least 2 weeks now. And I spent part of day trying to outline my plot and characters and gather together the notes I've strewn about various notebooks.
That's it then. Tonight at midnight I can start. Or I would if I weren't going to be on my way back from playing D&D with friends.
Good luck to all the brave (and mad) NaNoWriMos out there, including me!