Gitstalk - Discover what your favorite GitHub users are up to
GitHub Visualizer - Enter user/repo and see the project visually
Refined GitHub - Browser extension that makes GitHub cleaner & more powerful
Gource - Gource is a software version control visualization tool.
CodeMyUI - Handpicked code snippets you can use in your web projects
The GitHub Matrix Screensaver - Latest commits from GitHub visualized Matrix-style