When I go to the grocery store, I not only return my cart to the proper spot, but walk around the lot and return two or three others (one at a time). A good deed and an extra walk.
I use cooking time to sneak in a bit of exercise. If I'm standing by the stove, I do some squats. Pushups on the edge of the counter by the sink. March in place waiting for water to boil. You get the picture!
Instead of asking my husband to help carry in groceries or firewood, I do it. Extra steps, extra weight carried! (Don't worry, he still helps with other things!)
Instead of looking at unhealthy foods and thinking "I can't eat that," or "I shouldn't eat that," I look and say, "I DON'T eat that." I find this kind of proclamation makes it easier for me to stick to my principles of good eating. I don't eat fast food (and haven't in years).