There is a plant called Salvia Divinorum that Shamans used in ancient cultures which when smoked at a sufficient dosage, would provide psychedelic trips to such an extent in a ten minuet period that users would literally live the full, complete life of an entirely different person in an entirely different space and time. All within the confines of there mind.
Also, DMT. Over to Rogan...
http://www.youtube.com/watch?v=grcqs9cDuN8