The introduction to the aforementioned James Ernest's "Contact Juggling" describes the appeal of contact juggling beautifully:

"The illusion created is one of a free-floating, weightless ball, subject to unusual laws of motion. A good contact juggler can make his own movements seem almost unrelated to the movements of the ball; the attention of the audience is always fixed on the ball. Contact juggling is, above all, graceful and absorbing.

...

It is the mesmerizing quality of contact juggling that truly separates it from other forms. To take a single ball and cause your audience to sit quietly amazed; to do something so simple and obvious and still hear, 'How is that possible?'; this is the beauty of contact juggling. Juggling chain saws won't make them sit silently, and they won't ask you how to do it. Just why. And unlike producing a tiger from a fish tank, you can actually tell them how you do it, and they will still want to see it again."

With that said, if you are interested in contact juggling, you must first find a ball and then learn your first trick, the butterfly.