It's only around 9pm that I feel most awake and ready to work. I'll start looking at some personal projects (a new version of this site, editing and selecting photographs after scanning all of my film) and before I know it it'll 11 and I have to stop myself.
10 hours sleep a night minimum, and it's never enough. If I didn't need to be awake for work, I think I'd probably find myself on a 12/12 on/off schedule.