1. Will Rogers

In 1934, host Will Rogers (left) caused one of the most embarrassing Oscar mix-ups ever when he announced the winner of the Best Director award by saying, "C'mon get it, Frank!" Leaping out of his chair came Frank Capra, nominated for Lady For A Day. Capra was almost to the rostrum when he realized that Rogers had meant a different Frank. As Frank Lloyd won the award for Cavalcade, Capra slunk back to his seat. He later described it as "the longest crawl in history."

2. Bob Hope

In the record-holding 18 times Bob Hope hosted the Oscars, he spouted many quotable one-liners. But his most memorable moment came in 1966, when he was caught off guard by Best Picture presenter Jack Lemmon and Academy President Arthur Freed, who gave Hope an Honorary Award for his unique service to the motion picture industry. A visibly moved Hope was for once without a zinger, saying, "You've caught me with my idiot cards down."

In this summary clip of the 1966 Academy Awards, Hope receives his award at the 1:34 mark.

3. Jerry Lewis

1959 may have marked the only Academy Awards ceremony that ended early. With twenty minutes of air time left to fill, host Jerry Lewis stepped into the breach. "I proceeded to do shtick and bits and talk to the musicians in the pit," said Lewis. One bit was an uncomfortably long audience sing-a-long of "There's No Business Like Show Business." Undaunted, Lewis continued. "I went on until I ran out, then I brought everyone onstage and had a dance contest. I had Clark Gable dancing with Ann Sheridan. I had Cagney dancing with Bogart, and we danced until we went off the air." Lewis never hosted again.

In this interview with the Archive of American Television, Lewis recalls the short awards ceremony.

4. David Niven

In 1974, just as co-host David Niven was introducing the Best Picture presenter, a naked man streaked across the stage behind him. The debonair Niven took it in stride, quipping, "Isn't it fascinating to think that the only laugh that that man will ever get in his life is by stripping off and showing his shortcomings." It brought the house down. (In an official Oscars video on YouTube, stars recall their favorite Oscars moment—the streaker—with a clip of the streaker's interruption and Niven's quip.)

5. Johnny Carson

Johnny Carson brought his wit, charm, and perfect comic pitch to the hosting job five times. In 1979, he had one of the best opening one-liners ever when he scanned the star-studded audience and said, "I see a lot of new faces here, especially on the old faces." In closing the same ceremony, Carson told an ailing, cancer-stricken John Wayne that a "few friends want to say hello," then ushered on a galaxy of presenters and winners to fill the stage as a gesture of love and appreciation for the Duke.

6. Chris Rock

"Welcome to the 77th and last Academy Awards," cracked host Chris Rock as he opened the 2005 ceremony. (Watch the official Oscars video of Rock's opening monologue on YouTube.) Rock's fiery monologue didn't shy from politics, especially in a funny, barbed attack on President George W. Bush's mishandling of the country's economy. Rock said, "Just imagine you worked at The Gap and you're closing out your register and it's 70 trillion dollars short. The average person would get in trouble for something like that, right?" Rock hasn't hosted since.

7. Billy Crystal

Why is everyone excited to have Billy Crystal hosting again this year? Well, he's given us some of the most memorable openings ever to the Oscars. In 1992, he was wheeled on stage as Hannibal Lecter, complete with face mask. Crystal then walked into the audience, right up to Anthony Hopkins, and whispered, "Good evening, I'm having some of the Academy over for dinner. Care to join me?" (Watch the official Oscars video of his performance on YouTube.) And then there's Crystal's recurring "What are the stars thinking?" bit. In 2000, as the camera dwelled on Arnold Schwarzenegger, Crystal said, "I can't believe there's no party at Planet Hollywood... I can't believe there's no Planet Hollywood." Welcome back, Billy!