But there are plenty of other alternatives, that can be done with rental equipment...
Personal Watercraft (Jetskis)/speedboats
I tried searching for Beijing motocross/dirt bikes, but all I find is BMX. I don't want to ride a freaking bicycle, I want a real 100-250cc dirtbike that I can take to a mud track somewhere and tear it up! Barring that, I'll settle for kart racing.