LONDON -- These 2012 Olympics have been nicknamed the Twitter Games, the first in history to feel a major impact from social media as athletes share items including patriotic feelings and their lunch choices with legions of followers. Already, a racist 140-character joke by Greece's star triple jumper Voula Papachristou got her expelled from the Olympics on Wednesday, making her the first athlete in history to lose her spot for a social media posting.On the brighter side, Oscar-winning Slum Dog Millionaire director Danny Boyle, the man behind today's Opening Ceremony, was able to use Twitter to keep details of the show under wraps. After some details began to leak out at the beginning of the month, Boyle put a hash-tag to the situation. He created savethesurprise, which immediately went viral. The idea was to urge anyone who knew anything about the ceremony to keep it a secret. So far, it seems to be working.A crowd of 60,000 watched a dress rehearsal of the ceremonies Wednesday night, and savethesurprise was shown throughout the night on the jumbo screens, reminding them that sharing information or photos of the event was strictly prohibited.He also kept the surprise by leaving gaps in the rehearsals, so not even the show's entertainers know certain details. As usual, the most closely guarded secret is who will light the Olympic cauldron. Will it be two-time Olympic decathlon champion Daley Thompson? Rowing legend Steve Redgrave? Running sensation Kelly Holmes? Soccer icon David Beckham? None of the above? A combination of the above?This year, even the location of the Olympic cauldron remains secret. In Olympics past, the structure of the cauldron was in plain view, usually as part of the main stadium. Not this time. Most people assumed that the Orbit Tower, a 35-story red steel twisting sculpture next to the stadium, would be used as the cauldron. But the sculptor, Lakshmi Mittal, says it's not.So we are left to wonder.This much we do know about Friday's three-hour show:It is inspired by Shakespeare's The Tempest and will take us from pastoral England, with its green meadows and cricket grounds, through modern times, and then look toward the future. Its theme is officially Isles of Wonder. The show will begin at 9 p.m. local time with a James Bond character landing in the stadium via helicopter. Actor Kenneth Branagh will read excerpts from The Tempest.The second part of the show will tackle the Industrial Revolution, with performers dressed as miners and steel workers.Copies of London landmarks such as Big Ben and the Tower Bridge will be used somehow. And, of course, there will be a Beatles tribute. Sir Paul McCartney is among the entertainers scheduled to perform. The cast of the show is around 12,000. Although nobody expects them to replicate the jaw-dropping precision of Beijing's 2008 drummers, Boyle has high hopes the show will dazzle.The march of the athletes includes 205 delegations.The U.S. flag bearer will be fencer Mariel Zagunis of Beaverton, Ore. She was the first U.S. fencer to win a gold medal with her win as a 19-year-old in Athens eight years ago. She defended her Olympic title in Beijing and is the top-ranked women's saber fencer."I'm extremely humbled by this incredible privilege," Zagunis said. "As an athlete, I can't imagine a higher honor."