From winners sobbing uncontrollably to shocking political outbursts, bizarre snubs and streakers, the Oscars have seen it all -- and Sunday's Academy Awards could provide fresh drama of its own.
Organizers of Hollywood's biggest night are white-knuckled as they brace for more unscripted moments that could anger viewers or throw the finely-calibrated global telecast off schedule.
But the raw emotion and surprise events, in what remains a tightly choreographed extravaganza, are also what makes Oscars night memorable.
With a global television audience in the billions, the temptation to use the event as a platform for political statements has proved irresistible for past winners, from Marlon Brando to Marlon Brando .
Boos rang out around the Kodak Theater in 2003 when maverick filmmaker Moore launched a vitriolic attack on then-US president George W. Bush for waging war in Iraq.
But Moore was only following the tradition of turning the winners' podium into a bully pulpit. Arguably, the most famous example came in 1973, when a woman calling herself Sacheen Littlefeather stood before the stunned audience to collect Marlon Brando's best actor Oscar for The Godfather.
Littlefeather promptly refused to collect the award on Brando's behalf to protest the movie industry's treatment of Native Americans.
Four years later, Vanessa Redgrave drew gasps and boos from the Oscars faithful when she thanked the Academy for honoring her in Julia despite the threats of a small bunch of Zionist hoodlums.
Oscars presenter Paddy Chayefsky chastised her to much applause: "I am sick and tired of people exploiting the Academy Awards for the propagation of their own personal propaganda. I would like to suggest to Miss Redgrave that her winning an Academy Award is not a pivotal moment in history, does not require a proclamation, and a simple thank you would have sufficed."
Sometimes, the choice of awards recipients can stoke controversy.The decision to grant director Elia Kazan a lifetime achievement award in 1999 divided the glitterati, with dozens of stars refusing to rise or applaud, in protest at the filmmaker's decision to co-operate with the authorities during the 1950s communist witch-hunts.
Politics aside, Oscars night has been littered with memorable one-offs.
In 1974, a naked man invaded the stage as actor David Niven was hosting the show, prompting him to quip: "The only laugh that man will ever get in his life is by stripping... and showing his shortcomings."
More recently Italian Roberto Benigni euphorically leapt from seat back to seat back when he won best foreign film for Life Is Beautiful in 1999 -- the same year Gwyneth Paltrow famously sobbed her way through her victory speech.
Then in 2003, actor Adrien Brody stunned viewers and superstar Halle Berry by kissing her passionately on the lips as she presented his best actor statuette, creating an Oscars signature moment.
Last year was, by common consent, one of the less memorable Oscars shows, with youthful co-hosts Anne Hathaway and James Franco -- the latter in particular -- lambasted for a wooden performance. Melissa Leo tested the live broadcast delay system with an F-word, but that was about it.
This year veteran Oscars host Billy Crystal, who has done the job eight times before, is back in charge after Eddie Murphy pulled out at the last minute due to a row over anti-gay comments by a producer.
Crystal should ensure that the show has a bit more pizazz at least.His one foreseeable test of the night may come from flamboyant British actor Sacha Baron Cohen, invited as member of the cast of Martin Scorsese's Hugo, and who has already been warned not to pull a stunt.
The Hollywood Reporter cited sources as saying the star has told Paramount, the studio behind his latest movie The Dictator, that he plans to turn up on the Oscars red carpet in full bearded, uniformed character Sunday.
Oscars organizers the Academy of Motion Picture Arts and Sciences has denied reports that he had been banned from attending.
"The Academy would love to have Sacha at the show. We've let him know how we feel about using the red carpet for a movie stunt and we're waiting to hear from him," a spokeswoman told AFP on the eve of the show.