Gymnastics: A U.S.-China Olympic Face-Off

China's girls on bars and beams are adorable. Ours are, too. More important, though, the Chinese and U.S. women's gymnastics teams are the best in the world, making this the one sport in which the two Olympic powers can really go to the mats. The American squad might be even more accomplished than the gold-winning "Magnificent Seven" from Atlanta in 1996. Its four leading lights—Shawn Johnson, Nastia Liukin, Chellsie Memmel and Alicia Sacramone—have combined to win 25 medals in world competition. Last year the U.S. girls wrested the team title from China by less than a point (0.95). It was a reversal of the previous year, when China bested the United States by an even slimmer margin. The team final is Aug. 13, and a single misstep could be fatal.

Expect some fireworks on the men's side, too, with Paul Hamm returning to competition after a three-year hiatus. Hamm, the men's gold-medal winner in Athens, will have to shed the rust and rebound from a broken hand at the same time. His No. 1 challenger: China's Yang Wei, the reigning world champion.

If past Olympics are a guide, host nations always enjoy a boost—especially in judged sports, such as gymnastics. With so much parity between the Chinese and U.S. teams, home-gym advantage could wind up as the deciding factor.