Miley and the Lips got weird, Arcade Fire brought the funk and Billy Joel busted a gut on one of his favorite Paul McCartney tunes. In 2014, artists weren't afraid to shake off their own material and try on a few of their favorites. And with social sites like YouTube and Instagram more popular than ever, what could've been long forgotten, one-off live performances were shared worldwide for fans. These were 10 of the best.