A wrist rocket!! Many moons ago, when I visited a friend in the Houston area, we shot squirrels and rats off of power lines with these. Scary accurate ... though I wonder why his neighbor never complained about all the little white marbles in his pool :-) Thanks for the great memory!!
Yeah, they’re cool. They sell steel ball ammo for them now, no more searching for a “just right” rock. You’re right about them being very accurate with a little practice and, having taken a round to the backside many years ago, I can attest to their squeal like a pig, eye watering power.
Have you seen the "new" Wrist Rocket Pro? $36 or so, but looks like one hell of a piece of object-launching gear.
http://www.amazon.com/Saunders-Archery-Wrist-Rocket-Pro/dp/B000HE6E6I/ref=sr_1_1?s=sporting-goods&ie=UTF8&qid=1336925040&sr=1-1