Beyonce and Rihanna are some of the best movers and shakers in the business. Despite having the right dance steps, they still trip up every once in a while, solidly planting their face on stage. Sometimes these spills look like the singer will end up with a bruised knee, other falls look like they'll come out only with a bruised ego, but nearly all of them are hilarious. So, here is a compilation of some of the best of the worst concert fails.