Joaquin Phoenix (February 11, 2009)
Whenever this clip is shown, it's impossible not to feel bad for James Gray. The indie filmmaker, whose superb 2009 romantic drama Two Lovers starred Joaquin Phoenix, was probably thrilled to get the kind of promotion that a spot on the Late Show would afford his low-budget movie. Instead, Phoenix (and partner-in-crime Casey Affleck) hijacked the appearance for their own project, the faux-documentary I'm Still Here, in which the Oscar-nominated star "quits" acting for a hip-hop career — though Letterman wasn't in on the stunt. (You can tell from his Unabomber joke, which is biting, terrific and filled with disdain for his catatonic interviewee.) Phoenix returned a year later, sans hobo beard, to apologize. The great irony: Both Two Lovers and I'm Still Here sank like stones — but this appearance will outlive them both.