If you're like me you and like to learn from the best in our fields in high hopes that one day you to can be a guru in your field, Microsoft released some time ago the source code for all .NET Framework in cool site witch is powered by the new compiler Roslyn and where you can see how the c# gurus program.
It's very useful when you trying to understand what's happening behind the scenes and learn how to code well and follow great standards, all you have to do is navigate in your browser to http://referencesource.microsoft.com/, type a class name or any .net component and explore.
For instance in the image below, I typed "String" in the search box and the string class that every .net developer utilizes shows up and it's a enormous the amount of code in a "simple" class that we use in our day-to-day dev work.
You can check a short video on how to use this tool provided by Microsoft and their team.
Kudos for the .NET team and Microsoft's change of thinking on how to deliver tools and frameworks to the dev community and embrace the open source