The private pilot reported that he was landing the float-equipped airplane on glassy water at the conclusion of a local personal flight under Title 14, Code of Federal Regulations Part 91. He said immediately upon touchdown, the airplane abruptly flipped forward, and nosed over. The pilot and sole passenger exited the airplane uninjured and were soon rescued. The airplane sustained substantial damage to the wings and fuselage. The pilot indicated there was no preaccident mechanical problems with the airplane.