Keith Patton has started a CodePlex project called KandaAlpha which I will be contributing to.
Original post here
The aim of the project is get our feet wet with Visual Studio 2010 Beta 1 and in particular the POCO capabilities of Entity Framework.
It's also going to try and demonstrate best practice Domain Driven Design and other associated patterns.
db4o has been selected as the persistancy database of choice as it presents a very interesting alternative to the standard RDBMS.