I posted a demo of CubicVR.js vehicle physics which is mostly a test of of the RigidVehicle class but could easily be developed into a game, I'll probably make it available as a GitHub project soon and include the easily editable Blender file for the track.
There's also a great writeup on WebGL.com about it as well: http://www.webgl.com/2012/04/webgl-demo-cubicvr-stunt-track/
The live demo can be found here and is also available in the CubicVR.js GitHub repository samples:
http://cjcliffe.github.com/CubicVR.js/cubicvr/samples/vehicle_physics_demo/stunt_track1.html