Project Description
The Silverlight P2P library integrates Silverlight 2 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.

See http://firstfloorsoftware.com/p2plib/ for more details
Functionality
Reversi demo
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 the game is available as well.

Windows Live Activities require an Activity host (such as the Windows Live Messenger), you cannot just run the application in a web browser.

Running Reversi in the Windows Live Messenger
Requires two instances of the Windows Live Messenger and two Live accounts.