Today I added a new dumbbell exercise to my workout at the Y. This exercise is promoted as being for toning for bodybuilders, but I think it's perfect for runners as long as you use light weights. I think it's called the Dumbbell Run in Place. (I can hear the jokes now.) All you do is grab some weights and swing your arms.
I like this workout. It is challenging but not too strenuous. Plus, it's a good warm up for doing farm chores!