The master-clock in all mammals is the Supra-Chiasmatic Nuclei (SCN) which is the organ responsible for coordinating time-keeping in all cells within the organism. The SCN is composed of approximately 10,000 individual cells. Experimental evidence indicates that each cell in the SCN is an individual oscillator; inter-cellular coupling mechanisms (electrical and chemical) become important in synchronizing rhythms within a cellular network. After a brief overview of modeling approaches in this field, we will review current strategies for quantitative modeling of the SCN at the cellular and intra-cellular level. In particular we will discuss models which have studied the roles of molecular noise and inter-cellular coupling mechanisms in the SCN network; these model's results will be compared to experimental data. Ultimately we would like to understand the role of the SCN at the organismal level. We conclude with a general discussion/direction of the issues/questions in the next stage of SCN modeling.