Duolingo - Duolingo is a free language learning app for iOS, Windows and Android devices. The app makes learning a new language fun by breaking learning into small lessons where you can earn points and move up through the levels. Read more about Duolingo.

CS183B - Startup Class - Stanford class taught by Sam Altman & guest speakers

Eduflow - Digital learning that actually teaches students something

How to Acquire More Users - The growth guide used by Y Combinator companies

Backchannel Chat - Backchannel Chat is best in class discussion tool that is intended for teachers to streamline their class activities.

Velocity.js - Velocity is a JavaScipt animation engine.