The private pilot, operating the airplane under Title 14, CFR Part 91, was landing at an off-airport site for the third time that day. He said during the final portion of the landing roll, the left main landing gear wheel hit a bump, and bounced about 2 feet into the air. He said as the main wheel came down, the tailwheel hit the same bump, and the airplane nosed over. The pilot said there were no problems with the airplane prior to the accident. The airplane received substantial damage to the right wing and right lift-strut.