http://www-scf.usc.edu/~rashford/treehouse/index.html My friend put this web site together a little while ago, very interesting stuff. It's also a lot of fun. I've been trying to find other sets of travelling rings in other places I'm likely to go, like the bay area and Hong Kong, but I haven't had any luck. It's a lot of fun, and I suggest you all go check it out some time. The rings, that is, not just the web site.