Microsoft has posted a large example application using ASP.NET MVC to CodePlex. Called Oxite, this app is an extensible content management platform for blog hosting and large web sites. It is really intended for use by developers as reference on how to build large applications with ASP.NET MVC, but could be used in a variety of scenarios if you are so inclined.
Some of the features:
- Support for pingbacks and trackbacks
- Comment support for both authenticated and anonymous users
- RSS feeds (duh)
- Web admin (duh)
- Users can add new pages or sub pages
You can check out MIX Online to see a production web site built on Oxite. Oxite is the result of building the MIX site.