Multiagent systems is an attractive problem solving approach that is becoming ever more feasible and popular in today's world. It combines artificial intelligence (AI) and distributed problem solving to allow designers (programmers and engineers alike) to solve problems otherwise deemed awkward in traditional approaches that are less flexible and centralized. In the Fall semester of 2002, I introduced a new game-based technique to my Multiagent Systems class. The class was aimed for seniors (with special permission) and graduate students in Computer Science, covering some breadth and depth of issues in multiagent systems. One of the requirements was participation in four Game Days. On each Game Day, student teams competed against each other in games related to issues such as auction, task allocation, coalition formation, and negotiation. This article documents my designs of and lessons learned from these Game Days. The Game Days were very successful. Through role-playing, the students were motivated and learned about multiagent systems.