Plura sounds pretty cool. I had the vague notion a while ago that society could benefit by somehow using games to solve real-world problems (somewhat like on Stargate Universe). I'm glad to see this is being explored.
I like the idea too. Luis Von Ahn has done some work on tricking people to do useful things through play. 2 examples I can think of are Google Image Labeler(http://images.google.com/imagelabeler/), in which people provide useful metadata about random images on the web, and reCaptcha (http://recaptcha.net/), where captcha solutions are used to digitize parts of books where OCR fails.
