I've noticed I'm most creative when I'm super-tired. Late last night I was surfing on my laptop upstairs (yay!) when a cool idea hit me. I seem to remember reading reports about this phenomenon but now I can't find them. Maybe I'll find them late tonight. :-)
Another thing I had thought of last night was a rebuttal to Michael Sippey's rebuttal to Jakob Nielsen's new Alertbox, End of Web Design. And now I can't remember that either. I'll re-read it just before bed tonight and make sure to write it down this time.