I was recently visiting Corey Schuman’s blog since he has been focusing on Silverlight + Blend development for a while now. Among his posts I found his Blend section which contains information about behaviors and how to include a recommended Physics Library for Silverlight that allows you to create Physics behaviors by using mostly Blend.
I actually went ahead and watched the “Basics” video and I got so excited about how easy it seemed to play with it that I downloaded and installed the Physics Helper library and started to play with it right away.
from Anthony Baker more here