In this clicker case, students are introduced to George, an undergraduate student who has been experiencing some odd symptoms. His roommate convinces him to see a physician who recognizes that George's symptoms are consistent with diabetes mellitus; but is it type 1 or type 2, and how might you tell the difference? Participants in the case work together to obtain a diagnosis for George. The activity was developed as part of a larger project to increase case study teaching in anatomy and physiology by creating brief, modular, "plug-and-play" cases that are designed to easily integrate into more traditional class formats. The basic case presentation takes only 25-30 minutes of classroom time, with several suggestions for optional extensions within or outside the classroom. The case is formatted for easy use in large classrooms using clickers (personal response devices). The case was designed for an upper-level undergraduate course in anatomy and physiology, but could also be used in introductory biology, medical or nursing programs, or any human health-related courses.