Check out this INSANE video of some river surfing in Montreal....
Includes obligatory half naked surfer babes.....
http://www.2imagine.net/blogger2005/endless.html
Note: it turns into a somewhat lame Drago Rossi Squashtail add halfway through :-( Still they throw the odd flip turn and helix.... but I reckon the Orbit Fish looks like a nicer boat- yet to try it on a big wave though and it's a bit small for me anyway.