GitHub Visualizer - Enter user/repo and see the project visually
Awesome GitHub Topics - Top 500 topics on GitHub that's filtered and categorized
Codeology - Open-source algorithm that visualizes GitHub projects
git:logs - The definitive list of open source resources on Github
Octohunt - Search to find developers in your city on Github.
Mailbrew - Automated email digests from Twitter, Reddit, YouTube & more