The sun, moon, and stars are all rotating around a central point over the North Pole. The underlying cause for this rotation is a vast cornucopia of stellar systems orbiting around its center of attraction - an imaginary point of shared attraction. This is an extrapolated and more complex binary star movement. Think of a binary (two) star system which moves around an invisible common barycenter. Now add a third body which shares that common center of attraction. Now a fourth. When we add enough bodies the system looks like a swirling multiple system.
The stars in the night sky rotate around common barycenters above the earth just as the sun and moon do. From a location on the earth's surface the stars in the sky might seem to scroll across the night sky with Polaris at the hub.
Each star in a cluster is attracted to one another through gravitational vectors. Formation is created through gravitational capture - at least three objects are actually required, as conservation of energy rules out a single gravitating body capturing another. The stars maintain their movement over the years through Newton's first law: An object at rest tends to stay at rest and an object in motion tends to stay in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
The stars in the night sky trace almost perfect circles around the hub of the earth because by necessity the mechanics of a multiple system rely intimately on the movements and vectors of every member body. Circular movement is the most perfect, stable movement. If one celestial body is out of place or moves in a different fashion than the other bodies of the group the entire system becomes inherently imbalanced. Eddies, or stars that move out of tandem, will either leave the system entirely or are compelled by the stellar system to move back into its locked pace and apogee. This is why there are no elliptical orbits.
Instability in a multiple system can be avoided if the system is what astronomer David S. Evans has called "hierarchical." In a hierarchical system, the stars in the system can be divided into two smaller groups, each of which traverses a larger orbit around the system's center of mass. Each of these smaller groups must also be hierarchical, which means that they must be divided into smaller subgroups which themselves are hierarchical, and so on. In this case, the stars' motion will continue to approximate stable non-elliptical Keplerian orbits around the system's center of mass.
Here is an animation of a Multiple System, what one would see in the night sky over the hub of the earth:
Here is a scientific paper which describes the movements and behavior of Multiple Systems: http://adsabs.harvard.edu/abs/1968QJRAS...9..388E (external link)