Mirror the .NET framework source code on Github
It would really be helpful if the .NET framework source code was available for online browsing and referencing. Hosting the source code on GitHub would enable this as well as the ability to link to files and even specific lines of code. However the current code drop would need to be better organized before it is mirrored online. Organizing by folder/namespace would make it really easy to navigate.
Michael Paterson commented
I much prefer Github to CodePlex. CodePlex simply isn't nearly as usable.