China's Liu Xiang (R) celebrates as he crosses the finish line to win the men's 110 metres hurdle final ahead of Jamaica's Maurice Wignall (C) and Terrence Trammel of the U.S. (L) at the Athens 2004 Olympic Games August 27, 2004. China's Liu Xiang won gold in a time of 12.91 seconds ahead of Terrence Trammel of the U.S. and Cuba's Anier Garcia. REUTERS/David Gray

Supporters cheer for Democratic presidential hopeful Sen. Barack Obama, D-Ill., during a rally Tuesday, Feb. 19, 2008, in Houston. (AP Photo/Rick Bowmer)

Sheriff's Capt. Louie Perea talks about the shooting at a gun range of 29-year-old Australian twin sisters at the Arapahoe County Sheriff's office in Englewood, Colo., on Thursday, Nov. 18, 2010. Investigators met with the surviving sister on Thursday, who confirmed that they had planned to commit suicide together, and did in fact shoot themselves. (AP Photo/Ed Andrieski)

U.S. President Barack Obama greets Afghanistan's President Hamid Karzai (R) during the opening session of the meeting on Afghanistan at the NATO Summit in Lisbon November 20, 2010. REUTERS/Kevin Lamarque (PORTUGAL - Tags: POLITICS MILITARY)

U.S. President Barack Obama greets Afghanistan's President Hamid Karzai (R) during the opening session of the meeting on Afghanistan at the NATO Summit in Lisbon November 20, 2010. REUTERS/Kevin Lamarque (PORTUGAL - Tags: POLITICS MILITARY)

Obama family welcomes new puppy. (White House photo by Pete Souza)

In this Sept. 21, 2010 photo, Laramie Junior High School ninth-grader Kollin West poses wearing a "I (heart) boobies" bracelet in Laramie, Wyo. School officials objected to the bracelet, which is meant to raise breast cancer awareness, and ordered West to wear it inside-out because they considered the bracelet's wording inappropriate. (AP Photo/Laramie Boomerang, Andy Carpenean)

NEW YORK - SEPTEMBER 09: Rafael Nadal of Spain reacts after a point against Fernando Verdasco of Spain during his men's single quarterfinal match on day eleven of the 2010 U.S. Open at the USTA Billie Jean King National Tennis Center on September 9, 2010 in the Flushing neighborhood of the Queens borough of New York City.

Swiss tennis player Roger Federer celebrates after winning against Swedish tennis player Robin Soderling, during their quarterfinals match at the 2010 US Open tennis tournament September 8, 2010, in New York. Federer won 6-4, 6-4, 7-5.

Colorado Rockies' Jason Giambi watches the flight of a game winning walk off two-run home run against the Arizona Diamondbacks during the ninth inning of a baseball game in Denver, Sunday, Sept. 12, 2010. The Rockies beat the Diamondbacks 4-2. (AP Photo/Jack Dempsey)

Detroit Lions' Calvin Johnson lands in the end zone while playing the Chicago Bears during the fourth quarter of their NFL football game in Chicago, September 12, 2010. He did not score a touchdown on the play because officials ruled he did not have possession of the ball when he landed. REUTERS/John Gress (UNITED STATES - Tags: SPORT FOOTBALL)

CINCINNATI - SEPTEMBER 11: Pete Rose takes part in the ceremony celebrating the 25th anniversary of his breaking the career hit record of 4,192 on September 11, 2010 at Great American Ball Park in Cincinnati, Ohio. He was honored before the start of the game between the Pittsburgh Pirates and the Cincinnati Reds.