The GitHub Matrix Screensaver - Latest commits from GitHub visualized Matrix-style
LibHunt - LibHunt tracks mentions of software libraries on relevant social networks. Based on that data, you can find the most popular projects and their alternatives.
Octohunt - Search to find developers in your city on Github.
AlternativeTo - AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
Codeology - Open-source algorithm that visualizes GitHub projects
GitNews Web - Trending repositories from GitHub, HackerNews & Reddit