The value of simulations in the classroom is well established, and there are numerous publications that feature specific role-play exercises that can readily be introduced into the classroom. Frequently, however, instructors would like to design their own simulations to fit their specific learning objectives for a class, but don't know where to start. This article lays out a series of structural and design questions for instructors to consider in order to craft their own simulations. We recognize that there is no singularly "best" way to design simulations, so this article focuses on the key components of simulations and explores different possibilities for each of these components depending on the desired goals of the instructor. We begin with the basics of class size, topic selection, learning objectives, length, and timing. Next, we discuss the design parameters-including the nature of student interaction, desired output, background information, role-specific instructions, and a timeline for the phases of the simulation. We move on to considerations about the actual running of the simulation, and wrap up with reflections on debriefing, grading, and assessment. By stepping through the design questions that are summarized in the Appendix, any instructor, experienced or new to role-playing, can develop a custom simulation to help meet the learning objectives for their courses.