Plug for Sueetie!
The ASP.NET platform is great for fast development and Dave Burke has put together an open source application suite that is comprised of several other open source projects and tied together with a unified application manager. His This could be big. Sueetie is online! post describes the project and his manifesto can been seen at sueetie.org. This is a great alternative for those who can't afford the extremely high costs of Community Server and find that Graffiti cms can't meet their needs.
Check it out and get involved!