DARPA Network Challenge
To mark the 40th anniversary of the Internet, DARPA has announced the DARPA Network Challenge, a competition that will explore the roles the Internet and social networking play in the timely communication, wide-area team-building, and urgent mobilization required to solve broad-scope, time-critical problems.
The challenge is to be the first to submit the locations of 10 moored, 8-foot, red, weather balloons at 10 fixed locations in the continental United States. The balloons will be in readily accessible locations and visible from nearby roads.
The winning MIT team used a technique similar to multi-level marketing to recruit participants, with the prize money to be distributed up the chain of participants leading to successful balloon spottings, and all prize income remaining after distribution to participants to be given to charity.