Octohunt - Search to find developers in your city on Github.
Git Random - Chrome extension to replace new tab with random github user
CodeFlower - CodeFlower visualizes source code repositories using an interactive tree.
Code Climate for Google Chrome - Code quality and test coverage, directly in GitHub
SyntaxDB - Easily look up programming syntax for multiple languages
Devo - Devo delivers real-time operational & business value from analytics on streaming and historical data to operations.