Riverboarding is a sport I got into several years ago. It's like boogey boarding in a rapid. You actually catch the rapid and ride it for as long as you can . . . it's so dynamic. The rapid is constantly changing. The first time I went I went over "Maytag" on the North Fork of the Yuba River. It's a big Class 4 rapid with a drop of about 12' and with the flow up it's scary. Thankfully I didn't realize how dangerous it was until afterwards. I was with one of the top riverboarding guides, Bob Carlson who manufactured the first commercial riverboards and my buddy Dan Dominy, an adventure cameraman was there to watch too. I riverboarded a few more times on the American River and the Stanislaus but decided to move on but it was a great experience (the link below to a story about riverboarding on the American is exactly what I experienced). Check out these sites to learn more about riverboarding. Some people say riverboarding started in Europe and a few Californians eager to experience surfing on a river discovered it but others say that Californians invented it . . . . whatever it's more popular than ever.
Photo Gallery of Riverboarding
Riverboarding the American River an article