http://www.totaljerkface.com/happy_wheels.php

This is hilarious. My favorite character to use is Santa. LoL

Basically go to the site, Hit "Play", and pick a level. In the level description to the right, directly under the ratings, it will show you who the Playable Characters are. If it says "Any", then before the level starts you can pick whoever you want. Santa and his slave elves are awesome. hahahaha

I think I made a post on this a long *** time ago. I haven't played it in forever, they made a lot of changes and improvements. It's immensely fun with all those features they added. When I played it they only had 2 characters, lol.