This experiment demonstrates principles of decision-making in dynamic oligopolies, especially the difficulties in forming and maintaining cartels. As an illustration of firm behavior under imperfect competition, the game distinguishes between procedurally rational choices and substantively rational decisions in the context of collusive, Cournot, and competitive equilibria. The paper discusses results from an actual classroom exercise and suggests some additional variations in institutional details. Instructions for students and a spreadsheet program for producing payoff tables are provided in the appendices.