Make a set of tin can stilts with a couple of coffee cans and some rope. The kids will have fun walking around the yard on them.
Remove the labels from your coffee tins. Drill 2 holes, opposite each other, about an inch from the bottom of the tin. If the drill leaves any rough or sharp edges, you can smooth them quickly with a rasp or file. Thread a length of rope through the holes and knot each end tightly inside the tin, and voila! Stomp away!