The 2012 Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel was divided equally between Alvin E. Roth and Lloyd S. Shapley "for the theory of stable allocations and the practice of market design".
Put in the kind of language most of us can understand, Roth and Shapley won the joint Nobel for their work on the role of game theory and math in predicting stable economies. It all comes from the Gale-Shapley algorithm and its theoretical and practical applications. (That's why I'm including "math" among the labels here. Math teachers, this Nobel's for you!)
And that's it for Nobel Week. Quite a global experience, with plenty of ideas and people to research!