Winter fitness

Cyclocross season has just started and already I'm thinking about maintaining fitness over the winter. It's pretty harsh here in the winter, and I tried riding last winter at the expense of freezing my extremities to the point of falling off, then suffering unimaginable pain as they thawed out. Didn't like it. Not one little bit. And really, there's no fitness training going on when all my body is doing is trying to keep from freezing. I finally tried running, and that worked somewhat. Hell Week was perfect, and I started the season off pretty well actually. But I'd like to do better than pretty well next year. What do people do to stay fit in the winter? Or do they totally hibernate and start from scratch every year? Other than running, I've heard rollerblading at the 'dome works for some, spinning classes taught by local racers work for others, indoor trainers (sorry, I don't have the discipline for that!)... What works for you?