Space Blok XNA is a 1-4 player game for Windows Phone where the players use marbles to break a 3D block structure. The game utilises an open source physics library, BEPUphysics, to provide 3D simulation and realistic collision handling for the game objects.
This example is hosted in a Nokia Developer Project, where you can find additional documentation, discover recent revisions, and contribute to the project.
Watch a video about this example application.