Learney - Knowledge aggregator for developers

Party with a Local - Party with a Local is a free app that connects travelers with locals that want to party.

Multiplication Kingdom - Learn the times tables by playing and having fun in the Multiplication Kingdom (for kids and adults!)

Palaround - Meet people you should be friends with.

Khan Academy - Khan Academy offers online tools to help students learn about a variety of important school subjects. Tools include videos, practice exercises, and materials for instructors. Read more about Khan Academy.

Babble - A more personalized social network