Astral Projection is something I heard of years ago and never really put too much thought into it. Astral projection is "an interpretation of an out-of-body experience (OBE) that assumes the existence of an "astral body" separate from the physical body and capable of travelling outside it."(see Webster's New Millennium Dictionary of English) I watched the movie Insidious and that turned out to be what the movie was about. It made me think about it quite a lot. It is an interesting idea, when you go to sleep you dream and or have an out of body experience or both, and it feels as though you are actually travelling to a different place, almost in a different dimension as a spirit. In the movie it is just that that gets a young boy into trouble. After having inherited his astral projection or "travelling" skill from his father, he journeys too far into what is described as "the Further". In this astral plane there are bad spirits that wish to now inhabit the boys sleeping body (i.e. the empty vessel). I have always been a sleep walker and always have elaborate long dreams of which I can remember great detail. Sometimes I will spend what is days or a week in a dream. I've always seen it as a blessing and a curse. I have never experienced an out of body experience but have met others who have. Just recently I spoke with someone who said they had a few when they were in their twenties, which they attributed to religion and a soul. They actually felt that their soul had temporarily left their body. I asked about astral projection and explained what it was. They seemed to agree with the idea. I went on to elaborate on pseudoscience and we had a decent intellectual conversation over the matter. I don't necessarily believe in astral projection or the like but it is a nice explanation to something that is mysterious. Also it adds to humans almost a supernatural element (i.e. our ability to be dualistic and separate our soul from our body.) This may be why it is such a popular belief, because it makes humans sound capable of more than we are, naturally.
I even found a link to a website that has a three step process to prepare yourself for an astral projection. http://www.wikihow.com/Perform-Astral-Projection