Sourcegraph for GitHub - Browse and search GitHub like an IDE
Gource - Gource is a software version control visualization tool.
JSONView - Validate and view JSON documents.
Octohunt - Search to find developers in your city on Github.
JSON Viewer - The most beautiful and customizable JSON/JSONP highlighter that your eyes have ever seen.
The GitHub Matrix Screensaver - Latest commits from GitHub visualized Matrix-style