Silverlight.FX is a fantastic library by Microsoftâ€™s Nikhil Kothari. He has plenty of samples in the download of different uses.
A small and lean framework that facilitates more structured and more declarative app development (eg. separation of view/code, effects, behaviors etc.) using Silverlight.
Silverlight.FX is more than â€˜just FXâ€™, at the same time, it reminds of what you get from a library such as jQuery. Read more about Silverlight.FX
Download the code, try out the samples, etcâ€¦ Great stuff!