Pyrotechnics, faceless back up dancers and a one of a kind piano face off with Elton John -- Lady Gaga's performance at Sunday night's Grammy Awards was truly a spectacle that won't soon be forgotten. This isn't the first time Gaga has wowed the world with her often show stopping brand of "performance art". We've compiled the best from Gaga's relatively brief but prolific career-- blood, flames and plenty of computerized sunglasses after the jump. >>