Wow, Michael Phelps is going to retire after today.
The most decorated Olympian of all time swims in what he says will be the final race of his career—the 4x100-meter medley relay—tonight in London. It goes without saying that he'll try his hardest to go out on top. (The butterfly specialist can't do it alone, though—he'll be getting A-plus assistance from freestyler Nathan Adrian, backstroker Matt Grevers and breaststroker Brendan Hansen.)
But while that end-of-an-era event is sure to get the tears flowing, the second day of track and field competition brings all-new reasons to cheer—not least of which is the Olympic debut of South Africa's Oscar Pistorius , a double amputee whose carbon-fiber artificial limbs scored him the nickname "Blade Runner."
A four-time Paralympics gold medalist, the 25-year-old athlete has his share of critics who say his man-made limbs give him an unfair advantage.
But let's see how he fares in his 400-meter heat before we worry about it, shall we? Pistorius will also represent in the 4x400-meter relay.
Other must-see moments include:
• World-class American sprinters Allyson Felix, and first-time Olympians Carmelita Jeter and Tianna Madison will compete in separate 100-meter semifinals for a shot at darting past each other in tonight's final. Jeter's 10.83-second race was best among all quarterfinalists yesterday.
• The aptly named DeeDee Trotter, a relay gold medalist in Athens, runs for redemption in the 400-meter semifinals, four years after a major knee injury slowed the California native down ahead of the finals in Beijing.
• Other Americans to watch for in the pool: Jessica Hardy of Long Beach, Calif., will be paddling for dear life in the 50-meter freestyle, and 21-year-old Connor Jaeger will compete in the marathon of swims, the 1500-meter freestyle. We're tired just typing that.
• Serena Williams and Maria Sharapova, who will face off in today's women's tennis final at Wimbledon's All England Club, are both going to get their first Olympic singles medal—but only one of them will be gold.
• Two-time gold medalists Misty May-Treanor and Kerri Walsh-Jennings, who had more sand than usual to dust off after dropping a set for the first time ever at the Olympics in the last preliminary round, head into knockout competition against the Netherlands' Marleen van Iersel and Sanne Keizer.
• While most are still running it out for spots in future finals, medals will be handed out in the women's discus throw and the men's long jump.
• It's not just an Olympic myth—the women's individual trampoline final is today.
Other than that, enjoy the Games and happy royal spotting!