Switzerland’s Roger Federer celebrates aSwitzerland’s Roger Federer celebrates after winning against Colombia’s Alejandro Falla during their London 2012 Olympic Games men’s singles tennis match at the All England Tennis Club in Wimbledon, southwest London, on July 28, 2012. in London on July 28, 2012. AFP PHOTO/Luis Acosta.Serena Williams of the US celebrates aftSerena Williams of the US celebrates after winning against Serbia’s Jelena Jankovic during their London 2012 Olympic Games women’s singles tennis match at the All England Tennis Club in Wimbledon, southwest London, on July 28, 2012. in London on July 28, 2012. AFP PHOTO/Luis Acosta.US swimmer Michael Phelps reacts after hUS swimmer Michael Phelps reacts after he competed in the men’s 400m individual medley final swimming event at the London 2012 Olympic Games on July 28, 2012 in London.Olympics Day 1 – FencingLONDON, ENGLAND – JULY 28: Valentina Vezzali of Italy competes against Hyun Hee Nam of Korea during their Women’s Foil Individual Fencing Bronze Medal Bout on day one of the London 2012 Olympic Games at ExCeL on July 28, 2012 in London, England.South Korean Park Tae-Hwan poses on theSouth Korean Park Tae-Hwan poses on the podium with his silver medal after the men’s 400m freestyle swimming event at the London 2012 Olympic Games on July 28, 2012 in London.