Most of the source code for my physics demos is available on CodePlex (except for the WPF 2D one; I’ll get that moved at some point). To save you from having to hunt around I’m listing the main ones here. Enjoy!
Silverlight 1.1 2D (wheels)
One of my first Silverlight efforts, using the BulletX library; as soon as I get some time I’ll fix the irritating performance problem (stuttering frame rate), I promise!
WPF/XBAP 3D (beachballs)
One of my favorites (I like the specular highlights ) using the BulletX library. Don’t forget you can rotate the whole scene by dragging, or zoom in/out by right-dragging.
WPF / Flade (controllable car)
The already awesome Flade engine demo, running as an XBAP.
WPF 2D (car, eggs)
Demo (EXE): http://www.chriscavanagh.com/Chris/Source/WPFPhysics1_exe.zip
Source: http://www.chriscavanagh.com/Chris/Source/WPFPhysics1.zip, http://www.chriscavanagh.com/Chris/Source/NewtonDynamics.zip