[zer00eyz]

>> life-altering experience ... doesn't seem to make them a worse, better, or even different person

The best insight you will get, without taking the trip yourself is going to come from reading Huxley's "Doors of Perception". A large enough dose will give you all sorts of interesting insights into your own thinking.

The closest your going to come to this, is the first time you watch the film "The Game", assuming you pay close enough attention and are tuned into it as a film and the characters in it. However it pales in comparison to the real thing.