As a boy I spent many hours skipping stones across the surface of the water on the shore of Lake Michigan. The challenge was to get as many skips or as much distance as possible. Zero skips was a bust. One or two skips was disappointing, three or four skips was mediocre, and six or more skips was exhilarating. The angle of the stone with respect to the surface of the water seemed to be critical. A large angle approaching 45° produced one large jump and perhaps one or two more after that. A smaller angle produced more skips and a longer run. However, too small an angle would cause immediate sinking. Fine tuning the skill of stone skipping was a captivating pastime. Today stone skipping has become both a recreational and a competitive sport. Motivated students can explore the underlying physics of stone skipping to explain why stones skip, derive equations for the trajectory of an idealized skipping stone, and predict the number of skips and the total distance of travel of the stone. This problem can provide an entertaining exercise to consolidate knowledge of first-year physics, and an organizing theme for problem-based learning, without requiring advanced mathematics or a detailed description of the fluid flow around the colliding stone in three dimensions. Indeed, one can do for sidearm stone skipping what Poljak has done for overhand vs. underhand throwing to provide new insights: namely characterize physical variables needed to throw a stone as far horizontally as possible. Calculation of complete stone trajectories, including championship throws in competition, is possible. For example, Fig. 1 illustrates the trajectory of an idealized stone with model parameters tuned to enhance skipping behavior. The vertical distance scale is expanded to show detail. There are 67 skips over a distance of 114 meters. The pattern of a few early high skips, followed by a large number of low, quick skips is similar to that seen on recorded videos (search YouTube championship stone skipping).