From Wikipedia:

Contact juggling is a form of object manipulation that focuses on the movement of objects such as balls in permanent contact with the body. Having little in common with “toss” juggling, it most typically involves the rolling of one or more completely transparent balls on the hands and arms to create visual illusions, such as that of a ball fixed in space. It is divided into three main schools of technique:

1. bodyrolling is the manipulation of one or more props (usually spheres) around the hands, arms, and body, usually without the prop(s) ever being thrown into the air.
2. palmspinning is the manipulation of two or more spheres in each hand wherein at least one sphere is always in continual motion. Spheres may be transferred from one hand to another to form graceful and fluid patterns, but rarely are they ever released into the air.
3. isolationism is categorized by manipulation of usually one prop (again, a sphere of some sort or other toy such as firestaff) such that the prop appears to be suspended in time and place while the performer dances around it, usually in the Popping and locking styles.

Contact juggling is also known by other names, including “static juggling”, “sphereplay”, “orb rolling” and “dynamic manipulation”