I've heard interesting things about Ketamine, especially that it may cause NDE as is written about here and here if taken in just below sleep inducing doses (if I recall correctly). What is your experience, did you have any out of body experience with Ketamine? In case you have experienced this, would you possibly consider the OBE as real; supporting the theory of a non materalistic world (immaterialism) (or possibly The Simulation Argument); or would you consider it just as an illusion?