I have. I liked it. Several times. I'd do it again but... it
  lasts too long. 8 hrs. The first four are great: specialFX
  galore. The next four? You just wanna get to sleep because you
  have work/school the next day and food tastes like plastic, even
  in your stomach.

  But.. you have to be psychological stable more or less to do it.
  I suppose I am. All mine were good. The only bad moment was
  looking in a mirror and visualizing a scene from the Poltergeist
  movie where the skin on the face gets ripped off, but within a
  few seconds of, "woah omg" I started laughing at the absurd
  thing happening in front me. I KNEW then what tricks my brain
  was pulling on me, and found it funny, 'cause I knew it wasn't
  the least bit real.

  But do you need it? Did I need it? No.