Soccer
Since men's soccer made its Olympic debut 100 years ago, 15 different countries have gone on to win gold. Women's Olympic soccer is still a history in the making. After winning the inaugural gold in 1996, the American women are back to defend their title.

Goalkeepers need the best of both worlds -- excellent foot skills and quick hands. How else can they be expected to stop shots that are said to reach 70 mph? Goalies are allowed to use their hands only in the 18-yard penalty box.

"Walls" are typically used to protect areas of the goal during free-kick situations, and this four-player wall was no doubt designed to shut down the near post. However, like Wall Street in 1929 and the Berlin Wall in 1989, this wall's fall ... er, collapse leaves the near post exposed.

You've heard of the air ball, now try the "bending ball," a shot that curves in flight. In this case, the shooter's shot is designed to curve around the wall and just inside the near post.

Players aren't known for their height, which is a good thing. After all, guys like 7-foot-7 Gheorghe Muresan of the NBA might have trouble avoiding the 8-foot tall crossbars. Width isn't a problem. Even Sumo champ Akebono could squeeze between the posts, set 24 feet apart.

It's not unusual for an offensive player to put himself in the wall for tactical position. Still, it's highly unlikely this soccer version of the pick-and-roll didn't draw a whistle. In soccer, shoulder-to-shoulder contact is allowed, but unlike American football, tackling is out.