The popular DI.FM client for Windows Phone, Beem has been made open source. The client essentially allows users to connect to DI.FM servers and stream EDM (electronic dance music). Supporting both standard and premium streams, the developer has released the source code on GitHub with documentation for others to get involved and work some magic. It's all released under the Microsoft Public License (MS-PL).
Developers are able to use the code and release new apps so long as a few conditions are met (nothing major), and it's also worth noting that API keys have been stripped. Head on over to GitHub for the download and documentation.