Just saw this trailer for Pixel Boarder, a 2.5D physics-heavy stunt snowboarding game coming to XBLA. (IndieGames.com)
First thing that popped into mind after seeing this was an old freeware PC game called Ski Stunt Simulator. It's controlled solely with the mouse. If you want to jump, you have to swoop the mouse down then up quickly. By bringing the mouse down again you can then tuck into a ball sending yourself into a spiral of death-flips before you snap your skis off of your feet and flop down the side of a mountain! It's got a tutorial, a handful of levels with various objectives, and even a rocket pack.
There's even a Java version if you want to try it out in-browser, but I highly recommend grabbing the actual download. It's kind of the mouse iteration of QWOP.