Google Open Source - All of Googles open source projects under a single umbrella
Microsoft Visual Studio - Microsoft Visual Studio is an integrated development environment (IDE) from Microsoft.
Open Source @IFTTT - A collection of IFTTT OSS projects.
Visual Studio Code - Build and debug modern web and cloud applications, by Microsoft
Code NASA - 253 NASA open source software projects
Xcode - Xcode is Apple’s powerful integrated development environment for creating great apps for Mac, iPhone, and iPad. Xcode 4 includes the Xcode IDE, instruments, iOS Simulator, and the latest Mac OS X and iOS SDKs.