MiniBike Polo!
Mark found these guys last weekend and told me about it. We fixed up a 16" BMX bike (by putting on a much longer seatpost), built a few mallets, and showed up at 65th and I5 park and ride last night. It was a blast. The bike requirement is 16" wheels or smaller. I'm going to try and find one today.
Pictures are better than words. Click them for more.
On 7/7/7 there is Bruised By Bike, a tournament:
