I've been ocean kayaking a few times and a couple times on a calm river, but I've always wanted to shoot some rapids with one and learn how to do the roll. Except the whole "bonking your head on a rock and then you drown" part keeps me from trying it out.

After seeing some Olympic canoe and kayak events on TV today, I have to say the Olympic complex looks like the funnest waterpark in the world. A giant fake rushing river complete with foam boulders is a place I would feel much more comfortable learning the ropes of fast water kayaking. I wonder if any of these exist in the US?