For those of you unfamiliar with clicker personal response systems, a clicker is a handheld remote that students use to enter their responses to multiple choice questions. The question is displayed on the classroom overhead screen, usually within a Power Point presentation, and a receiver connected to a computer at the front of the room collects all responses, grades and stores each response, and (when requested) highlights the correct answer and displays a bar graph showing how many students chose each option. Here the author shares his personal experience using clickers during large introductory biology courses. (Contains 1 figure.)