Since then, I have gotten some exercise every day for over six weeks. I think I can call this a habit now. Given my historical lack of enthusiasm for exercise and difficulty with keeping resolutions, I regard this as nigh-miraculous. Go me!
Sometimes I work on our Gazelle exerciser for the duration of a half-hour TV episode (without commercials, because I'm watching on DVD); more often, I get my twenty minutes walking. (Light exercise was fairly explicitly part of my contract with myself; I didn't feel I had the oomph for heavy exercise every day, but I'd have much more luck sticking to a routine that involved 'every day' than one that was three times a week.)
There have certainly been a few cases where I skirted the edges of my rule, but I've kept it up pretty faithfully. I once gave myself credit for the twenty minutes after discovering that I'd walked only fifteen minutes each way to a restaurant for lunch, and once gave credit for a fifteen-minute walk uphill followed by ten minutes each way from my car to the store in a parking lot.
I was worried about how this habit would hold up for our road trip. I knew that I could stick to the original rule by not playing WoW on days when I got no exercise--but I've felt a certain pride in the "exercise every day" pattern, and I'd feel sad if that daily winning streak got broken.
On Monday, I took a walk late while Lori was packing; on Tuesday, we went for a walk in the park. So I've maintained my winning streak with exercise, even though I haven't been playing Warcraft.