CodePlex really is a fun place. Super easy source control with Visual Studio Team Explorer and lot's of project management functionality. Because I like it so much, I have moved another Silverlight project to CodePlex as well. This time it's the Silverlight P2P Library that is available at http://www.codeplex.com/SilverlightP2P.
The First Floor Silverlight P2P library integrates Silverlight 1.1 (Alpha) with Live Messenger Activities, introducing the concept of Silverlight Activities. The Silverlight class library exposes the P2P Activity API. Included is a managed representation of the P2P API in an abstract P2PApplication class. This base class completely hides the details of JavaScript interop and the unmanaged P2P communication layer.
In order to demonstrate the functionality of the P2P library, the game of Reversi has been implemented as a Silverlight activity. The source code of this game is available on CodePlex as well. If you want to play the game in the Windows Live Messenger, go to the Windows Live Gallery and invite your buddies for a game of Reversi.