Since he was old enough to sit in a stroller, I have been taking Casey along with me when I go jogging. In the beginning, I would just talk to him while I ran (whenever I had enough wind in me to run and talk at the same time). Lately, we've been able to hold conversations as I run. Undoubtedly, the conversations center around the various types of vehicle we see. Big trucks, ambulances, city busses, school busses, fire trucks; he calls them all out.
Recently, we added a twist to the program. It was the first time Casey and I went running together. As in, no stroller. We would alternate between running and walking. (And sometimes, he would sit or lie down on the ground). Then I would say, "Casey run" and he run again. He did great, we reached our destination, where of course, he had energy to spare.