On January 22, 1995, about 1410 eastern standard time, a Glassair III, N300FF, registered to Jack G. Rouse, experienced an on-ground loss of control during a touch-and-go landing at Willis Gliderport, Boynton Beach, Florida, while on a 14 CFR Part 91 flight. The airplane nosed over and came to rest inverted sustaining substantial damage. Visual meteorological conditions prevailed and no flight plan was filed. The commercial pilot and commercial pilot/passenger were not injured. The flight originated from Willis Gliderport, Florida, 1 hour before the accident. The pilot stated he was making a touch-and-go landing. The nose gear started a violent shimmy after landing, turned perpendicular to the path of travel, and the airplane nosed over. A witness who observed the landing confirmed the pilot's statement, and stated the elevator was in the full up position during the landing rollout. Examination of the nose gear by an airframe and powerplant mechanic revealed no evidence of a failure. The cause of the reported shimmy in the nose gear could not be determined.