Farscape Scorpius Ball
This prop first appeared in the series on Scorpius's desk. The rumor is that they were originally on the desk of one of the show's producers. While filming the scene the director realized they needed something for Scorpius to do so Wayne Pygram ran down to the producer's office and stole them. In a later episode Chrichton is seen playing hockey with one.
While they are never explained in the series or shown to have any function they are a found prop. They are designer decorative accessory balls sold by Ethan Allen. They came in two sizes and were fairly expensive at the time. They are no longer being produced and are exceedingly difficult to find for such a pointless item. I managed to pick up some of the larger size on ebay in 2009, two of which were copper and one brass.
As an interesting aside I found out that one of these was also used in the 2005 reboot of the Doctor Who series as a piece of the Tardis control console.