Swimming
The Michael Phelps farewell tour heads into its final days as he goes in the 100 butterfly finals. He holds the world record in the event. Also, Katie Ledecky will most likely become the first person to sweep the 200, 400 and 800 freestyles since 1968. Friday is the 800, which is her best event.
Track and field
It's considered the Games' marquee sport, but it starts out a little slow. There are finals in women's shotput and 10,000 meters. Tirunesh Dibaba of Ethiopia, considered the best of all time, has five Olympic medals, including three golds in distance running. There also will be qualifying in the women's 100 meters and the men will do a little early work in the 400 and 800.
Basketball
The U.S. men struggled in their last game against Australia until Carmelo Anthony lit it up in the fourth quarter. Friday's game against Serbia probably won't be as interesting. With Spain not playing as well as most predicted, there is a good chance the U.S. men and women will go undefeated. The women, more dominating than the men so far, face Canada.
