A witness reported that the airplane departed the field at 1030, eastern daylight time, on May 27, 2007. According to the witness the RV6 returned to the airport and attempted to land. The airplane had already made one go-around. On the second attempt the aircraft appeared to be slow and "mushy" at the south end of the runway. The aircraft had traveled about 800 feet down the runway when it stalled approximately 60 feet above the runway. The aircraft descended and "hit hard" and bounced back into the air approximately "30 or 40 feet". No power was applied and the airplane landed hard again. The nose gear of the airplane broke and the airplane nosed over inverted. Examination of the airplane by an A&P mechanic under the supervision of an FAA inspector revealed no anomalies with the aircraft structure or flight control system.