On July 13, 2003, about 1030 Pacific daylight time, an experimental Maysmike Pitts S1S, N25SF, ground looped during the landing roll out at Livermore Airport (LVK), Livermore, California. The pilot was operating the airplane under the provisions of 14 CFR Part 91. The pilot was not injured; the airplane sustained substantial damage. The flight departed Livermore about 0900 for the local area personal flight. Visual meteorological conditions prevailed and no flight plan had been filed. In a written statement, the pilot reported after practicing touch-and-go's at Byron Airport (C83), Byron, California, he returned for landing at Livermore, runway 25. The touchdown was normal except for a "slight bounce." During the roll out, the left wing lifted and the airplane turned slightly to the left. The pilot applied "rudder correction with [the] stick full back." The airplane continued to turn left and he attempted differential braking; however, the airplane continued to turn left. The airplane came to rest facing about 90 degrees left of the runway heading. The right wing sustained a broken spar and broken ribs, and the right landing gear was bent during the turn. The Federal Aviation Administration (FAA) inspector examined the airplane. All flight controls functioned properly and no preimpact anomalies were found. The winds reported by the Livermore Aviation Routine Weather Report (METAR) at 0953 were 240 degree at 6 knots. The winds reported at 1053 were 230 degrees at 7 knots.