Practice effects are ubiquitous human phenomena that have been scientifically studied for over half a century. They are also among the most directly applicable psychological phenomenon, holding broad implications for any domain involving human expertise, and especially for education. Yet the details of how practice works to improve performance are often poorly understood by the users of this phenomenon, such as teachers and coaches. In this paper I describe a simple classroom activity, The Seeker Game, which introduces students to the basics of practice effects, and to some of its complexities. After describing the game I suggest directions for discussion, focusing on "Microgenetic Analysis," a method that exposes the sources of performance change in detail. This analysis reveals the multifactorial nature of change, demonstrating that performance change often takes place not primarily in participants' heads, but spanning the cognitive, physical, and social domains.