Go out and run. That's how I've been coping with working doubles and nasty weather. I'm an idiot sometimes, but I'm not dumb enough to go out riding at 9 PM with a marginal lighting system and with snow and ice on the road. However, I'll throw on some of my old running shoes and hit the streets for about 45-60 minutes, just to keep the fitness up and the blood flowing.

Just avoid the sidewalks, I guess.