Basketball
There are some key rules differences between NBA, WNBA and international rules. And these differences could provide other countries with their only advantage over the latest U.S. Dream Teams.
Since Dream Team I cruised in '92, the world has drawn a bit closer as the American margin of victories has shrunk. But it's easier for the United States to play without Kobe and Shaq than it is for Lithuania and Yugoslavia to be without Sabonis and Divac, respectively.
The trapezoidal shape of the Olympic key increases the size of the lane, making three-second calls and crowding of the low post more common. This encourages a perimeter offense, thus possibly explaining why so many Europeans can drain from downtown.
International game is slower. The shot clock is longer and the zone defense is allowed. One might think the U.S. would be at a disadvantage, but NBA players don't even need 24 seconds to score, much less the international (and WNBA) 30.
The Olympic 3-point line (20 feet 6.1 inches) is closer than its NBA counterpart (23 feet, 9 inches at top of arch). A closer line means advantage NBA-ers, right? Just wait until Vin Baker decides he can hit from that range.