Ran across this interesting info (that all fathers should know) over on 10ticks:
At present the world record for skimming a stone is set at 38 bounces. French scientists from the Institute de Recherche sur les Phenomenes hors Equilibre have studied the art of skimming. A throw involves four factors- the translational and spin velocities, the angle at which the stone heads for the water and the angle at which it hits the water surface. To get near the world record, Christophe Clanet, the head of the team recommends the angle to approach the water is about 20 degrees, spinning at 14 times per second and with a starting speed of 25 mph. Jerdone Coleman-McGhee is the world record holder and passes on these tips: Triangular stones skip best, circular stones are less stable. The lower your hand at release the better. Strength is not the key, quickness is. The faster the stone is spinning the better it will skip. The surface of the stone should be parallel to the water when it hits to achieve maximum bounce. The very finest skipping stones are flat black slate.