in .NET Framework

A CMS that integrates into ASP.NET MVC

Here is a open source CMS called N2 that provides a CMS framework to build web applications on using the ASP.NET MVC Model.   Its a very basic CMS, but it provides all the core functionality including Pages, Articles and a .NET Permissions Model (it also has some add ons and allows developers to contribute their own add ons).   They have lots of documentation and useful examples on how to work the CMS with MVC.   Very cool stuff!