And within hours of the announcement contributions were already being accepted!
You can browse and search the projects that Microsoft has made public on GitHub over on their landing page.
This isn't the first team from Microsoft to join us on GitHub - the Microsoft Azure, Microsoft Open Tech, TypeScript and ASP.NET teams are already on GitHub, collaborating in the open with the community.
If you're one of the 6 million developers building applications using .NET, this is your chance to contribute to the future direction of your development stack. Check out the GitHub help site or GitHub Guides to learn more about contributing to open source.