State of Open Source in .NET 

Links to ASP.NET Open Source Projects 

Get statistics for open source coders

Check the activity of open source projects  

Microsoft .NET Open Source Software Projects Showcase 

From Closed Source to Open Source: A Journey 

We’re using Web Components in a big way at GitHub. We have over a dozen open-source Web Components  and with dozens more that are closed source.

One SQL unit testing framework which I have been using lately is tSQLt, which is a simple open-source framework. 

AutoMapper has been a popular library in the .NET open source community for a long time. As their site says:

AutoMapper is a simple little library built to solve a deceptively complex problem - getting rid of code that mapped one object to another. This type of code is rather dreary and boring to write, so why not invent a tool to do it for us?