30 Seconds to Mars

Thirty Seconds to Mars turned in a faithful cover of Rihanna's spare ballad 'Stay,' yet Jared Leto and the boys still managed to make it decidedly Thirty Seconds-ified. It's an utterly breathtaking version of RiRi's hit.

Lady Gaga is a mega-star. She's one of very few actual "artists" that exists in the music world. She's eccentric, eclectic, and, let's face it, effing weird. Which is why 30 Seconds to Mars loves her. This is why they performed a  cover song of one of her early hits, "Bad Romance."