Used to know a slightly odd, hyperactive kid in high school who used to randomly 'head-tap' my friends and I on the shoulder (with his forehead). Every once in a while we turned it into a bit of a game where you tried not to let the other head tap your shoulder. It's basically tag but arms-free (or maybe 'thumb wars' works as an analogy, for its dodgy nature)...and you can only give chase or escape by walking fast, no running.<p>Coincidentally or not, we were also ultimate frisbee players in middle school. And there were pogs, of course.