Justin Bieber, Selena Gomez Kiss Among Billboard Awards Highlights

Show also featured a Rihanna/Britney lip-lock and a tribute to Beyoncé.

They say that what happens in Vegas stays in Vegas, but on Sunday night, pop culture lovers everywhere were treated to a festival of debauchery and fun at the Billboard Music Awards, which were held in Sin City and broadcast live on ABC.

There were two kisses that will certainly have people talking for days. When Britney Spears took the stage with Rihanna for their sexy performance of "S&M," the two shared a kiss. Of course, Spears isn't new to onstage girl-on-girl lip-locks, having shared one with Madonna back in 2003. On Sunday, Spears also took the stage with Nicki Minaj, but no spit was swapped during that other girl-power performance.

Perhaps a more surprising kiss occurred when [artist id="3187077"]Justin Bieber[/artist] kissed girlfriend [artist id="3079282"]Selena Gomez[/artist] after it was announced that he won the award for Top New Artist. Although he didn't mention her name in his speech, according to Aceshowbiz.com, Bieber later praised his lady love in the press room, saying, "She's amazing." Bieber took home five other awards Sunday night.

Beyoncé, honored with the Millennium Award, received taped tributes from Bono, First Lady Michelle Obama, The-Dream, Stevie Wonder, Barbra Streisand and Lady Gaga. As memorable as her performance was thanks to some eye-catching visuals, killer dance moves and that barely there outfit, her shout-out to Jay-Z certainly stood out. "I love me some Jay-Z," she said, after calling him her "best friend."

Bey also thanked those who have been in Destiny's Child, including founding members LeToya Luckett and LaTavia Roberson as well as Kelly Rowland and Michelle Williams; Rowland and Williams were in the crowd cheering their girl on.