Dogecoin is an open source cryptocurrency like Bitcoin. Indeed, Dogecoin uses Bitcoin as its underlying codebase; the difference between the two is that Dogecoin has a ridiculous, hilarious, and enthusiastic community. The nice people who mine Dogecoins have done a lot for fund-raising for good causes:
Find out more at Dogecoin Foundation.
The community is so filled with fun and joy that it inspired me (and the rest of the team at Wero Creative) to make AstroDoge. The game captures the goal of the Dogecoin community: to the moon! In the game you steer a spaceship in between asteroids by only controlling the thrusters.