I just discovered Orchard CMS, and I must say that based solely on the open source projects upon which it relies, it looks like a GREAT platform. Namely, AutoFac, Log4Net, NHibernate, Castle Windsor, Moq, and SpecFlow. Just the fact that the developers are using these architectural and testing tools tells you that they know a lot of something about a well-designed .NET project. Not to mention the long list of .NET ninjas and Microsoft devs that contribute to it. I'm looking forward to diving further into the source code and perhaps using it on a future project.