5. Keith Urban and Gary Clark Jr.
56th Annual Grammy Awards, January 26th
Gary Clark Jr. had already been nominated for awards in two different genres — Best Traditional R&B Performance, which he won, and Best Rock Song, which he lost to Paul McCartney — when he jumped onstage with Keith Urban midway through the 2014 Grammys, rounding out the evening with a little country twang. The two frontmen traded verses, guitar solos and punches during a four-minute performance of "Cop Car," with Clark adding some grit — in the form of flubbed lyrics and a few less-than-perfect guitar bends, none of which soured the overall vibe — to a song that might've otherwise sounded too squeaky-clean.