This article doesn't do a very good job explaining what it is that makes psychedelic drugs so intellectually interesting. I'd recommend listening to Terence McKenna talking about his childhood and how he discovered psychedelics.

http://matrixmasters.net/archive/TerenceMcKenna/215-McKennaT...

Alternatively, listen to Alicia Danforth's amazing talk on giving psilocybin to terminal cancer patients to ease end of life anxiety:

http://vimeo.com/10931182