MIT’s entry has won the DARPA Network Challenge, which had teams using the Internet to find 10 red balloons placed around the country, from Portland Ore., to Katy, Texas, to Christiana, Del.

The MIT team cleverly outsourced the search to … everyone, more or less, in a convoluted pyramid scheme that paid cash to the finder of a balloon, the person that invited the finder to the competition, the person that invited that person and a charity.

Researchers on the team used the scheme to learn about how social networks spread information.