Man that's good. Not sure if it's staged. I'm leaning towards staged. Any case it's really good, Letterman is quite funny.
Either it was staged or Joaquin Phoenix was fucked up on hallucinogenics.
Occam's Razor would suggest the latter as it is the most simple explanation. Also, I have a sixth sense for noticing people that are on LSD, call it a survival instinct but that man could sell me a sheet if I walked up to him right now.
-420