EFVincent talks about the concurrency optimization in Silverlight 3. Very interesting post. A lot of explanations and code.
About a week ago Joa Ebert posted Flirting with Silverlight, in which he discussed his experiences with a cool little Lorenz attractor application. The strange attractor app (which you can check at his blog) was his way of playing around with the newly released Silverlight 3 (Props to Joa for some very cool work BTW). It calculates a shape in 3D defined by some 300,000 particles, and animates the spinning and rotating of this shape as the user moves the mouse across the display surface.