I heard about Duolingo, but I have not tried it before today. I decided to try a Spanish lesson and set it up for 5 minutes a day. I ended up completing 5 times more than planned and enjoyed this game-based experience. This awesome product was born as a result of collaboration of a teacher and his student. I like how initial idea was transformed as the two smart brains joined to come up with a solution. In addition, they were able to build relationships and raise $80 million.