Tyson Gay vs. Usain Bolt in Olympic 100 Meters

No Olympic sport has had more star reputations ruined by doping than track and field. Sure, cycling, swimming and weightlifting have all taken big lumps. But so many heroic runners have turned into goats—Ben Johnson, Tim Montgomery, Justin Gatlin, Marion Jones—that we don't feel the same excitement about the new kids on the blocks.

Long before doping tainted the sport, though, Olympic immortals like Jesse Owens and Wilma Rudolph wove the sprints into the American sporting fabric, and the titles of "world's fastest man" and "world's fastest woman" still have special resonance. Even now it's hard not to feel a thrill when the runners toe the line for the 100-meter dash.

In Beijing, the men's showdown will be among the most anticipated in these Games. American Tyson Gay figured to be the favorite after sweeping the 100-200 double at last year's world championships. Then came a bolt of lightning—21-year-old Jamaican Usain Bolt, who exploded past Gay en route to a world-record time of 9.72 seconds. Just weeks later, though, Gay ran a wind-aided 9.68 at the U.S. Olympic trials, the fastest 100 in history (though the tailwind will keep his time out of the record books). Circle Aug. 16 on your calendar: that's Gay vs. Bolt, the rematch.