I like to call this dreamwalking. It usually happens when I'm totally relaxed - stoned or just daydreaming. It's pretty much like dreaming awake - I get vivid visions that, if I'm careful, I can control and interact with. Yesterday I had this vision of myself as a schizophrenic, where I backed myself up in telling a friend to quit bothering me about not having any ambition. It was pretty messed up.

It's usually fun though. By observing what your subconscious thinks about you can unlock personal barriers. Dreaming can be a very useful tool.