Learnist.

Learnist is a website that allows users to post on various topics and allows readers to learn about any topic they want. They brag that “you can learn just about anything via Learnist”, and it’s true! I myself asked a few random questions and wasn't disappointed. The websites feel is playful and homey which is very clever for what they are trying to "sell"! Great colors, clean layout.

http://learni.st/