When actors unleash their inner lunatic, it's not only a chance to steal every scene, it's a surefire shot at an Oscar as well -- if only we could be convinced that they're really acting! Which of these legendary performances dangled audiences the furthest over the very mouth of madness? Angelina Jolie in Girl, Interrupted or Brad Pitt in 12 Monkeys? And will anyone ever trust either Kathy Bates or Glenn Close with sharp objects ever again?