To elaborate on Zhan's post...the term is "lucid dreaming" and it describes the condition when one is concious of the fact that they are dreaming, therefore having control over pretty much everything within their little dream world. I've heard a good way to practice lucid dreaming is to train yourself to look at clocks. Apparently the written language recognition in your brain is completely shut off while you sleep/dream. So in theory (I've never tried it - this is coming from my Pysch prof.), you could look at a clock in your dream, see that it's either blurred or just gobbledy-gook, and come to the conclusion that you're actually dreaming. Once you're past that step, you can pretty much do whatever you want.
Lol, it's funny that Zhan bought chocolate because I've also read that most people either have sex or fly during their first Lucid dream. [img]i/expressions/face-icon-small-tongue.gif[/img]