Ballistocardiograms (BCGs) are graphical representations of the recoil from the pumping action of the heart. Introductory mechanics and a basic knowledge of the circulatory system are sufficient to understand the key features of a BCG. BCGs with adequate detail for instructional purposes may be produced easily and rapidly using hardware (a force plate) and software common to introductory physics labs. The interdisciplinary nature of this exercise is a particularly attractive feature. We have used it as a demonstration in a course on mechanics for nonphysics majors as well as for visiting high school students, and indicate here possible ways to incorporate it into upper-level physics or biomechanics courses.