Since its launch a few months ago, the Urgent Evoke Alternate Reality Game has been providing virtual motivation for players to solve problems in their real-world communities.  Linking games to social activism, Evoke is a project from the International Bank for Reconstruction and Development, targeted primarily at children in Africa.  However, Evoke is by no means restricted to that audience; anyone can join in.  The comic strips (which are very well-made) and tutorials on Evoke’s homepage can tell you more:  http://www.urgentevoke.com/