Game Theory

"Game theory is a study of strategic decision making. More formally, it is "the study of mathematical models of conflict and cooperation between intelligent rational decision-makers."
Think "Prisoner's dilemma".


Application of or Game theory won him 2012 nobel prize:
http://en.wikipedia.org/wiki/Alvin_E._Roth#Case_Study_in_Game_theory

Stable marriage problem is very interesting.  Algo is clear and easy to understand.  Interesting part is that there can be multiple solutions and stable may not = optimal:
http://en.wikipedia.org/wiki/Stable_marriage_problem#Optimality_of_the_solution