The inertial exerciser and entertainment device includes a central axle on which is mounted pair of pendulums. Each pendulum includes an elongated pendulum rod, a spherical weight provided on one end of the pendulum rod, and an eyelet provided on the other end. The pendulum rods and the spherical weights of the exerciser are configured such that when the pendulums are mounted on the common axle, side by side, the spherical weights are aligned and are configured to oscillate and collide in the same plane.