Getting people to work together is difficult. Getting people who don't know each other to work together is very difficult. Getting people who don't know each other to work together over the internet is nearly impossible. Enter Transformice
is elegantly simple in its premise. A number of mice, usually 25, have to get some cheese and take it to their hole. In their way are a number of obstacles, gaps, pits, bombs and, unfortunately, each other. Every mouse is controlled by a player, and one player gets to be the shaman, who can conjure various bits of apparatus to help the mice in their quest.
The game strikes a fine balance between teamwork and competition - the mice get more points the faster they get the cheese to their hole but they often need to wait for their shaman to construct them a path. The points are important as whoever has the most points at the end of a round becomes the shaman for the next round.