(CNN) -- As celebrities walk down the Oscar red carpet Sunday in front of the Dolby Theatre just ahead of the 86th Academy Awards, they may want to ponder time, space and con artistry.
The best picture front-runners express aspects of all three. "12 Years a Slave" is a searing look at a tragic era in America's past, about a free man taken into Deep South slavery in the 1840s. "Gravity" is set in outer space, where an astronaut comes to terms with herself.
And the third favorite, "American Hustle," is a loose, laugh-filled look at a pair of shifty professionals and their involvement with a political scandal.
"Hustle" and "Gravity" led all films with 10 nominations each, and "12 Years" received nine.
Other films up for best picture are "The Wolf of Wall Street," "Captain Phillips," "Philomena," "Dallas Buyers Club," "Her" and "Nebraska."
But there are several stories to follow as the 2014 Oscars approach -- including a number of firsts if either "12 Years" or "Gravity" take a pair of big prizes.
If Steve McQueen wins best director for "12 Years," he'll be the first black director to win the Oscar. "Gravity's" Alfonso Cuaron would be the first Latino director to do the same. "Gravity" would be the first science-fiction film to become best picture.
"History will be made either way," says awards watcher Clayton Davis of AwardsCircuit.com.
Jennifer Lawrence, who won best actress last year for "Silver Linings Playbook," could become the first person to win consecutive acting Oscars in different categories. She's up for best supporting actress this year. Meryl Streep, who's nominated for her record 18th acting Oscar, could win her fourth -- tying Katharine Hepburn for the most wins by a performer.
Even Brad Pitt could win an Oscar. He's one of the producers of "12 Years a Slave."
Still, the main attraction of the 2014 Oscars isn't so much the winners. It's the event -- a showbiz extravaganza once described by Johnny Carson as "two hours of sparkling entertainment spread over a four-hour show."
Among this year's segments is a tribute to the 1939 film "The Wizard of Oz," which is celebrating its 75th anniversary this year. CNN's Piers Morgan talked with the children of "Oz" star Judy Garland -- Liza Minnelli, Lorna Luft and Joey Luft -- on the red carpet.
Asked who was the best singer in the family, Minnelli -- an Oscar winner for "Cabaret" -- responded quickly.
"Mama, we all know that," she said.
This year's host is comedian Ellen DeGeneres, known for her chipper banter and way with a joke. She'll have plenty of targets.
"It has lately turned into something that's a little more about the clothes than the performances, and I will comment on that," she told The New York Times.
Ah, yes. "Who are you wearing?" It may not be Bjork's swan dress or Sharon Stone's Gap turtleneck, but somebody will likely attract attention for an outfit that's a little out of the ordinary.
This year there's an extra challenge: the weather. The Los Angeles area has been hit by thunderstorms over the last few days, though as of midafternoon Pacific time, the sun was out and the precipitation had passed. Still, it may be a little damp as the stars make their way inside.
And despite all the handicapping, all the predictions, all the chatter and arguing and folderol, right now only two people know the winners: PricewaterhouseCoopers' Rick Rosas and Brian Cullinan, who have spent the last few days supervising the counting of the ballots. They'll be backstage handing the envelopes to the presenters -- and their lips are sealed.
And nobody will change that, Rosas says.
"Not even the head of the academy knows," he says.
The 86th Academy Awards are scheduled to begin at 8:30 p.m. ET Sunday. The show airs from Hollywood's Dolby Theatre.