On July 27, 2008, about 1415 central daylight time, an amateur-built Bolenbaugh Rans S-6ES, N402PB, piloted by a sport pilot, sustained substantial damage when it nosed over during landing. The airplane was landing at the ultralight airstrip at the annual Experimental Aircraft Association fly-in at Oshkosh, Wisconsin. The flight was operated under the provisions of 14 CFR Part 91 and was not on a flight plan. Visual meteorological conditions prevailed at the time of the accident. The pilot received minor injuries. The flight originated from Juneau, Wisconsin, about 1340. The pilot reported that during landing he touched down about 35 percent down the 1,200 foot grass runway and the airplane bounced. He decided to put it "right back down." As soon as the airplane touched down again, the pilot applied brakes with the airplane on all three wheels. He said that the airplane nose wheel entered a "dip" in the runway that "appeared to be somewhat soft" and the nose landing gear collapsed. The airplane's nose then struck the ground and the airplane nosed over. The pilot reported that the accident could have been prevented by executing a go-around when the airplane bounced. The pilot reported no preimpact malfunctions of the airplane. The reported winds at the time of the accident were 270 degrees at 6 knots.