This article describes an exercise that simulates one of the most famous of all human management problems: the “tragedy of the commons.” Coined by Garret Hardin in 1968, the term refers to any situation in which people acting rationally to meet their individual interests wind up depleting a shared resource to the detriment of all participants. Because these patterns arise in many real-world situations — from global warming and natural resource management to free-rider problems in markets and organizations — this exercise may interest a broad range of negotiation scholars, teachers, and practitioners. The Chocolate Conundrum is a simple exercise that uses candy to demonstrate the tension between individual and collective interests that arises in all social dilemmas. Because these dynamics also arise in many real situations, the exercise can be a powerful teaching tool for instructors in management, public policy, sociology, economics, and many other social science disciplines. Unlike some other simulations of collective action problems, this exercise is simple to administer, requires no computation or tallying of results, and works with a broad range of audiences and group sizes.