Although many students have some knowledge of patents, it can be difficult for them to understand the components of an innovator's decision-making process. Key issues, such as whether to patent or to use trade secrecy, how broad a scope to claim, and what to do in the event of patent infringement, can be difficult to grasp from a standard lecture. The authors present a classroom exercise in which students assume the role of an innovator and their decisions at each stage have direct consequences on the profits they earn. Realistic probabilities are used to determine whether patents are infringed or court cases are won. The exercise is additionally useful in providing lessons on behavior under risk and uncertainty and the profit-maximizing goal of firms. (Contains 9 notes and 3 tables.)