Miami turned up the heat even more than usual on Sunday as MTV's Video Music Awards (search) converged on the spicy city for the first time in the awards' 21-year history.

The star-studded show included several surprise appearances, but the most striking theme of the night was a strong "get out the vote" message. Performers including P. Diddy, Usher (search), OutKast (search) and John Mellencamp all encouraged the viewers to vote in the upcoming presidential election.

While OutKast, who took home best video of the year award for "Hey Ya!," closed out the show, audience members held signs that said "Vote," "Choose or Lose" and other non-partisan election slogans. OutKast's "Hey Ya!" also won the best hip-hop video award, best special effects and art direction.

OutKast tied Jay-Z (search) for the most awards with four each. Jay-Z came into the night with the most nominations, six total including video of the year.

But this year's show was devoid of the outrageous debauchery it's become famous for.

Normally, the awards take a backseat to the wild stunts that performers surprise fans with. But this year, after the criticism of last year's Britney Spears-Madonna kiss and the breast-flashing of Janet Jackson at the MTV-produced Super Bowl halftime show, MTV was taking precautions to prevent any additional firestorms.

For the first time, there was a several-second tape-delay of the live broadcast (the network has used an audio delay for years). The audio delay was in heavy use during the hip-hop medley, which featured Lil Jon, Petey Pablo and Fat Joe.

The censors may have been extra-ready when comedian Dave Chapelle was on stage.

He joked of his appearance: "It's the biggest mistake you made since Janet Jackson at the Super Bowl!"

The show kicked off with Usher bare-chested and getting soaked with simulated raindrops as he sang his ballad "Confessions." Later, he took home the award for best male video for "Yeah!" with Lil Jon and Ludacris. The same trio also nabbed the best dance video award.

"This is my first time coming up here — let me take my time with this," a beaming Usher said. "I'm so damned happy right now I don't wanna leave."

No Doubt (search) won the first major award of the night for best pop video for "It's My Life." It was handed out by Will Smith and Miami Heat's Shaquille O'Neal. No Doubt later took home the best group video award.

Early in the night, Jay-Z got the award for best rap video for his haunting black-and-white video for "99 Problems." The video, which depicts his own killing as a symbol of his "retirement," also won for best editing, cinematography and direction.

"I felt like I was trying to push the envelope," said Jay-Z, who looked dapper dressed in white suit and hat. "That was my punishment and this is my reward."

Singer Beyonce (search), who is also Jay-Z's girlfriend, won for best female video for "Naughty Girl."

Later, songstress Alicia Keys (search) took home the best R&B video award for "If I Ain't Got You."

This year was the first time MTV presented an award for best videogame soundtrack. The winner was for "Tony Hawk’s Underground."

The best new artist in a video award went to Maroon 5 for "This Love." The MTV2 award was given to Yellowcard for "Ocean Avenue." And the best rock video winner was Jet for "Are You Gonna Be My Girl."

In one of the more awkward moments of the night, Alexandra and Vanessa Kerry, the daughters of Democratic presidential candidate John Kerry, came on stage to encourage young people to vote, and were met with boos. President Bush's daughters, Jenna and Barbara, also appealed to young voters via satellite.

The backdrop of politics was evident throughout the night. "The Daily Show" host Jon Stewart (search) made several appearances via satellite as he monitored the status of the viewer's choice award of the evening — and even briefly interviewed former presidential hopeful Rev. Al Sharpton.

The viewer's choice award went to Linkin Park for "Breaking the Habit."

Rap impresario P. Diddy, who has been working on the "Vote or Die" campaign, also urged the audience to show up at the polls on Nov. 2. And while accepting an award for best dance video, Usher told people to "vote or die."

A surprise appearance came from Mary-Kate and Ashley Olsen. It was the twins' first public event since Mary-Kate was hospitalized for an eating disorder.

"Thank you to everyone — you have been very supportive for the last couple of months," Mary Kate said before introducing Jessica Simpson.

In another unexpected twist, while singing "Jesus Walks," Kanye West brought Chaka Khan up on stage with him instead of just using a sample of her voice.

In a strange stunt, Flaming Lips singer Wayne Coyne appeared on stage enclosed in a big plastic ball pushed by fans on the arena floor. But perhaps the most surreal, and bizarre, performance came from the Polyphonic Spree, the rock choir that performed in multicolored, choir-like robes.

Keys gave a soulful performance of her hit "If I Ain't Got You," and was buoyed by Stevie Wonder on harmonica. Moments later, she joined Wonder and Lenny Kravitz as they sang a classic Wonder hit, "Higher Ground."

Keys also appeared on stage to honor the late Ray Charles, who died in June.

There was a lavish start to the evening when stars such as Simpson arriving on the red carpet by luxury yacht. She and her husband and "Newlyweds" co-star Nick Lachey floated in on a 68-foot boat.

The biggest entrance came from P. Diddy, who was dressed in a white suit and had a mohawk haircut. He arrived in a towering yacht along with rapper Ma$e, model Naomi Campbell and actor Bruce Willis.

The show, held a day before the Republican convention was to kick off in New York City, ended on a patriotic note as red, white and blue balloons fell from the rafters and fans held "vote" signs during OutKast's closing performance.

The awards capped a weeklong celebration in Miami, as celebrities such as P. Diddy, Paris Hilton and R. Kelly held star-studded parties leading up to Sunday's festivities.

"Everyone just wanted the excuse to go down to Miami for the weekend," said MTV President Van Toffler.

The Associated Press contributed to this report.