astral projection. i try very hard, and rarely do. when it's Samhain however, i have to try very hard to stay in my body. even if i don't want to, once i lie down, i feel like i'm being pulled out of my body. when you get into a very relaxed state, and the veil between worlds is weak, sometimes, people will ap on their own. they won't go far, just be slightly outside the body. any shock will send you back. there's a theory i've been told about that many people are projecting slightly above their body when they sleep, and another that dreams are really projections.
there's another form of AP, i forget what it's called, it's like dreamming really hard, or guided meditation, where you mind travels but your astral self stays. can't remember it though, the books been packed away so if you want to know what i'm talking about mail me, but i won't be able to reply for about a week.