One of the most important challenges facing college instructors of economics is helping students engage. Engagement is particularly important in a large-enrollment Principles of Economics course, where it can help students achieve a long-lived understanding of how economists use basic economic ideas to look at the world. The author reports how instructors can use Classroom Response Systems (clickers) to promote engagement in the Principles course. He draws heavily on his own experience in teaching a one semester Principles course at the University of North Carolina at Chapel Hill but also reports on how others have used clickers to promote engagement. He concludes with evidence that students find clickers very beneficial and with an assessment of the costs and benefits of adopting a clicker system. (Contains 5 figures, 2 tables, and 17 notes.)