to extend the model is to allow for the effects of external forcing. This generalization is theoretically natural, but it is also motivated in part by experimentally observed phenomena \[Kiss et al. 2008\]. For example, consider the way that the daily cycle of light and darkness helps to entrain our sleep, body temperature, and other circadian rhythms to the world around us \[Moore-Ede et al. 1982, Dunlap et al. 2003, Foster and Kreitzman 2005\]. Like all mammals, each of us has a circadian pacemaker, a network of thousands of specialized clock cells located in the region of the hypothalamus known as the suprachiasmatic nuclei, just above where the optic nerves criss-cross as they make their way back to the brain. These cells have been shown experimentally to be intrinsically oscillatory \[Welsh et al. 1995\] and their distribution of natural frequencies has been measured \[Liu et al. 1997\]. The pacemaker cells are also known to be mutually coupled, though their precise connectivity remains unclear. Thus, qualitatively at least, one could try to model the pacemaker cell network with the Kuramoto model. Now consider how this network might respond to an imposed cycle of light and dark (information of this sort is 