Kalam Labs - Twitch for Science
Call2friends - High-quality cheap and free international calls online to any mobile or landline numbers from internet and free calling app - cheaper than other VoiP providers. Try it now!
MathCrunch - Learn math stress free
Make Free Calls Online - Make Free Calls Online is a web application that, as the name suggests, allows its users to make international and local calls for free.
Code Fight Club - A fight club you can talk about. Less punching, more coding.
Poptox - Poptox is a web application where you can communicate with people in every corner of the world.