(In honor of my first day kayaking on the river!)
First of all, when it comes to whitewater kayaking, there are basically two schools, the river-runners and the playboaters. The purpose of river-running is to get from point A to a lower point B on the river, through whatever flatwater and whitewater is along the way. Playboating is for those with more of an addiction to whitewater. Instead of traveling down the river, playboaters often park & play at a particular spot on the river that has a good wave, hole, or rapid. They then perform "tricks" in the waves, much in the way that snowboarders and surfers do. A great playboater can actually get their boat airborne. Of course, many river-runners do tricks too, on whatever exciting river features they encounter along the way. It's not uncommon for river-runners to eddy-out near a hole then hang out in the same area and play for awhile before continuing on down the river.
Some of the basic tricks:
A front surf involves remaining on a feature of the river (such as a wave or a hole) without being washed downstream. From this position, many moves can be initiated. A back surf is identical to the front surf, but with the boat facing downstream, making it slightly harder than front surfing. A side surf is done with the boat oriented perpendicularly to the current. Carving involves moving back and forth across the face of a feature.
The basic spin involves rotating the boat parallel to the surface of the water while surfing a feature. The rotation must be greater than 180 degrees to count as a spin. Performing a 180 degree spin is similar to beginning an aggressive carve, transitioning through a side surf, and ending in a back surf. A clean spin involves using a single stroke to spin through multiple ends. A flatspin involves lifting the upstream edge of the boat from the water during the spin.
A double pump is the basic move to sink one end of the boat. The boater begins by simultaneously putting the boat on edge, making a quick back stroke, and leaning backwards. Immediately after this stroke, the boater leans forward and pushes down hard on the same paddle blade. The boat should now be perpendicular to the surface of the water, with the bow down in the water and the stern up toward the sky. A cartwheel is a move performed while surfing a hole or on flat water, in which the boat rotates perpendicular to the surface of the water. The move is initiated with a double pump. The paddler's torso functions as the axis. Once vertical, the paddler continues the rotation, alternating ends. The paddle is used to press down on the water on the downstream side of the boat, alternating hands as the boat changes direction.
In a loop, the boater does a complete flip, landing in the same direction that the move was initiated. The move is begun like a popup, with the paddler driving straight and flat into the most powerful part of the current on a feature. The boater leans forward, and the bow is swept down and the stern up. Once vertical, the paddler quickly leans backward to pop up out of the water, then powerfully drives forward to intentionally cause the boat to become over-vertical. If done properly, the stern should catch in the current and the boat will return to its starting position. A back loop is identical to a front loop, but is performed backwards, both starting and ending in a back surf.
These are then combined into combo tricks, many of which have funny names like phoenix monkey or space godzilla. Many kayakers design and name their own combo tricks.
Disclaimer (for Mom): None of these tricks involve waterfalls of any kind : )
2nd Disclaimer: Portions of this post were shamelessly lifted from the "playboaters" link above.