Adam Kinney saw a tutorial which demonstrates a very cool way to dynamically apply a torn weathered effect to a photo in Flash and decided to do the same in Silverlight.
In Silverlight, the WriteableBitmap class is used to manipulate bitmap data. The current class is pretty low-level, providing access to the bits, but not many convenience features. Thankfully a few community members have started an open source library called WriteableBitmapEx. This library extends the functionality of the WritableBitmap class to include methods for drawing, blending and more.