What are some large, model-rich open source applications?

I need to identify a large model-rich open source ruby, c-sharp, objective-j o开发者_运维问答r java applications so that I can target them for a series of projects. Are you guys aware of any that I could use?

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Kigg is a Digg clone written in best of breed ASP.NET MVC with Enterprise Library and a ton of other cutting edge practices.

http://www.codeplex.com/Kigg