Abstract: This invention is a pendulum structure that operates as near as possible as a perpetual motion machine to provide activity and entertainment to one using same. The pendulum structure includes: (1) a housing assembly; (2) a pendulum assembly mounted within the housing assembly; and (3) an actuator assembly connected to the pendulum assembly. The housing assembly includes a bottom assembly connector by a wall assembly to a top assembly. The bottom assembly and the top assembly are substantially identical, each being of a tray shape, having a bottom wall section with integral side wall sections and end wall sections. The wall assembly is preferrably constructed of a transparent material having a front wall and a back wall interconnected by opposed side walls. The front wall has an arcuate slot therein to gain access to the interior of the housing assembly. The pendulum assembly includes a basic support member and a pendulum member attached by a connector assembly to the basic support member.