I am a geriatric anthropologist. My specialty is end of life tennis ball usage. Did you know that people over 62 use 83% of the worlds tennis balls? It's true, a large portion are used to keep those razor sharp walker legs from "snagging the carpet" or "scratching the formica". They also make great memory aids. Simply pop one on the antenna of the Buick and voilia no more confused calls to the grand kids from Wal-Mart's parking lot. The automotive applications are nearly endless. In fact many Cadillac models have an optional tennis ball console. After all you can't have that chrome trailer hitch exposed to the elements during the four hours a week that the car is out of the garage. Perhaps the most amazing use that the elderly mind has devised for the tennis ball is to suspend one on a string from the ceiling of a garage. While modern science has yet to explain how, this will in fact stop a moving vehicle.