Here are five things to look out for at the London Olympics on Saturday:
1. HISTORY MADE: Oscar Pistorius became the first amputee to run in an Olympic track event, winning his 400-meter heat on carbon-fiber blades.
2. 100M DASH: On the eve of the much-anticipated final, Jamaica's Usain Bolt limbered up with a heat victory in 10.09 seconds and compatriot Yohan Blake made it in 10.00. American Tyson Gay finished his in 10.08.
3. FAREWELL PHELPS: It's the end of an era. Michael Phelps swims his last competitive race, the 4x100 medley relay. It's one the Americans have never lost.
4. TENNIS FINAL: It's Maria Sharapova vs. Serena Williams for Olympic gold at Wimbledon.
5. US MEDAL HAUL: They've set themselves an overall target of 30 track and field medals. How many will the Americans manage Saturday?