The Wikipedia Adventure
The Wikipedia Adventure is an interactive guided tour / tutorial / learning game. It teaches new Wikipedia contributors basic editing, cooperation and collaboration skills. It introduces project mechanics, philosophy and policy. The setting is an interstellar mission to outer space. The focus is a hypothetical article about Earth. Participants receive rewards (in the form of badges on their user pages) automatically after completing each of the 7 missions. The adventure takes approximately one hour to complete.
Learning to edit Wikipedia can be "hard", "frustrating", "confusing", and "overwhelming" for some editors. The purpose of this game is to create a directed, purposeful, positive, and fun learning experience. Rather than walk away from the site feeling like it is incomprehensible—or worse—threatening, users graduate from The Wikipedia Adventure ready to face the challenges and opportunities of the real site and community.
The Wikipedia Adventure was built in 2013 through an Individual Engagement Grant from the Wikimedia Foundation. There is more information about TWA on English Wikipedia  and on Meta wiki . Slides 9-15 of this presentation cover the need for a tool like TWA and some of the strategies it uses. 
There is interest in translating and localising The Wikipedia Adventure for other language Wikipedias. This would be very helpful for Wikipedia Education Programs around the world. If you are interested in doing so or have already done so, please indicate that here.