The 2013 Billboard Music Awards are rolling into Las Vegas on Sunday. It's shaping up to be a great show, with Taylor Swift, Justin Bieber, Jennifer Lopez, and Lil Wayne scheduled to perform, while Madonna will be honored with the Top Touring Artist award. Before we check out all the action this weekend, though, we're taking a look back at the Billboard fun in years past. Remember when Jessica Simpson and Nick Lachey took the stage together in 2003 or when Britney Spears heated things up with Rihanna in 2011? Click through to see all the photos, and check back later for coverage from the show!