Whitewater is a term that covers all sorts of canoeing, especially when there is a wave involved.  For extreme experiences, paddlers will take the smallest of their playboats and head to any wave, sometimes found in a river, but more than not in the surf. There are competitions for freestyle and others for the fastest down the river. Boat handling and reading the water hydraulics are skills essential to this sport. Check out the clubs page for a whitewater club near you.