Competition in track and field finally begins Friday at Olympic Stadium. In addition to medal events in the women's 10,000 meter and men's shot put, there will also be numerous qualification rounds, including ones for the women's 100 and 400m races as well as men's 400m hurdles and long jump.
Michael Phelps will swim the last individual race of his Olympic career Friday after qualifying fastest in the 100-meter butterfly. Phelps will be coming off a win over Ryan Lochte in the 200 individual medley Thursday, his 20th Olympic medal and 16th gold. He has won the 100 fly the last two Olympics, including his now famous .01-second victory over Milorad Cavic in Beijing.
The last men's sprint final, for the 50-meter freestyle, is also Friday. World record holder and defending Olympic champion Cesar Cielo of Brazil and Cullen Jones of the U.S. tied for the fastest time in the semis at 21.54 seconds.
American Anthony Ervin, the 2000 Olympic champion who sold his gold medal to aid victims of the Indian Ocean Tsunami and came out of retirement after nine years to give the Olympics another try, qualified third fastest.
Medals will also be handed out in the women's 200 backstroke and 800 free. Elizabeth Beisel and U.S. teammate Missy Franklin qualified 1-2 for the final of the women's 200 back while Britain's Rebecca Adlington, the world record holder and 2008 gold medalist, swam the fastest heat for the women's 800 free.
The U.S. women's soccer team has a quarterfinal match Friday against New Zealand. The two-time reigning Olympic champion Americans, who went 3-0 in group play, would play the winner of the Great Britain-Canada quarterfinal in the semis on Monday. Sweden and France will also play quarterfinal matches Friday, as will Brazil and Japan.
Semifinal action in singles and doubles highlights Friday's tennis schedule.
Switzerland's Roger Federer will try to get a step further toward his goal of winning a gold medal, as he faces Argentine Juan Martin del Potro. Andy Murray, Great Britain's gold medal hope, takes on Serbian star Novak Djokovic.
In women's singles, American Serena Williams faces Belarus' Victoria Azarenka, while Maria Sharapova plays fellow Russian Maria Kirilenko.
Serena and her sister, Venus, will also try to move on to the final of the women's doubles draw. They face Russians Kirilenko and Nadia Petrova. It could be an all-USA final, as Liezel Huber and Lisa Raymond take on the Czech duo of Lucie Hradecka and Andrea Hlavackova.
The American Bryan brothers, Mike and Bob, are in action in a men's double semifinal. Mike Bryan and Raymond are also playing in a mixed doubles quarterfinal.
Judo competition wraps up Friday with the men's 100kg-plus and women's 78kg- plus classes. Among the women competing will be Wojdan Shaherkani, the Saudi Arabian judoka who was told she had to compete without a hijab, thus jeopardizing her participation. However, after an agreement was reached, she was allowed to compete with a headscarf. She is one of the first two women Saudi Arabia has sent to the Olympics.
Track cycling continues with two medal events -- the men's team pursuit and women's keirin -- and qualifying for women's team pursuit. Great Britain's pursuit team set a world record Thursday, and is the clear favorite, while Australia and New Zealand should also be competitive.
Women's keirin and team pursuit make their debuts in the Olympics. Following a disappointing result in Thursday's team sprint, when she was relegated out of medal competition, Great Britain's Victoria Pendleton will try for gold. But Australian Anna Meares is the two-time defending world champion.
In boxing, there is round of 16 action in the men's flyweight and welterweight classes. American flyweight Rau'shee Warren received a bye into this round, and faces France's Nordine Oubaali. In the welterweight category, the USA's Errol Spence fights No. 3 seed Krishan Vikas of India.
Gold will be up for grabs in two shooting events, with the men battling in both the 50-meter Rifle Prone and the 25m Rapid Fire Pistol. Alexi Klimov of Russia is in the lead after qualifications for the pistol. Both the qualifying round and finals of the rifle prone will be held on Friday.
In fencing, the men's team sabre tournament will take place and Russia is favored to win gold. The United States will face the top-seeded Russians in the opening round on Friday.
The gold medal match in badminton mixed doubles will take place on Friday and it will be an all-Chinese affair with Zhang Nan and Zhao Yunlei against compatriots Xu Chen and Ma Jin.
The first medals in gymnastics trampoline will be handed out on Friday and China's Lu Chunlong if favored to repeat as the gold medalist in the men's individual competition.
Friday could mark the biggest moment of Katherine Grainger's rowing career as the women's double sculls final is set to take place.
Grainger is one of the most successful rowers in Great Britain's history, but has yet to capture an Olympic gold medal. She and partner Anna Watkins had the fastest time in the semifinals and haven't lost since teaming together three years ago. They'll be challenged by Australia's Brooke Pratley and Kim Crow, who is also racing in the single sculls.
New Zealand's Eric Murray and Hamish Bond are likewise unbeaten since teaming up and they go for gold in the men's pair. The men will also row for medals in the quadruple sculls and single sculls, where Britain's Alan Cambell is one of the contenders.
The men's individual archery tournament wraps on Friday at Lord's Cricket Ground and the U.S. has already lost its best chance at a medal after world No. 1 Brady Ellison was knocked out of the draw. American Jacob Wukie is also out.
Great Britain's Larry Godfrey, the fourth seed, will try to please the home crowd with a gold, will South Korean ranking-round world-record holder Im Dong Hyun, who is legally blind in one eye, shoots for the title. Viktor Ruban, the 2008 gold medal winner from the Ukraine, is also still in contention.
Group play in women's basketball is starting to wind down and China, France, Russia and the U.S. have all already guaranteed themselves spots in the quarterfinals.
The Americans continue their rounding into medal form with a matchup against the Czech Republic.
Australia and Turkey hope to advance on Friday. The Aussies can punch their ticket with a win over Russia, while Turkey aims to rebound from a loss to the USA with a win over China that would put it in the quarters.
Also Friday, medals will be handed out in weightlifting in the women's 75- kilometer category and the men's 85kg group. There are preliminaries for women's 3-meter springboard diving and quarterfinals and first round team matches in men's and women's table tennis.
Beach volleyball begins its knockout stage on both the men's and women's side and equestrian continues, with the Ann Romney-owned horse Rafalca, ridden by Jan Ebeling, in dressage competition again. Women's preliminary play in handball is in action, as is men's pool play in field hockey and opening series in seven sailing disciplines.
The U.S. women's indoor volleyball team has a match against Serbia, one of six preliminary games Friday, and the U.S. women's water polo team plays China among four preliminary matchups on the schedule.