Lucid dreaming is a pretty fascinating phenomenon. You may have heard of it. A lucid dream is one where you realize that you are dreaming and thus can consciously control what happens to you. They are often more vivid than normal dreams, depending on how "lucid" or self-aware you can be throughout the experience.
What I find particularly interesting is the way that you influence a dream. To make something happen or come into being in the dream world, you expect it to be so, until it is. This says a lot about how perception operates. If you're interested in learning more, I'd recommend starting with the book On Intelligence, by Jeff Hawkins. It presents what is probably the most viable hypothesis that I've yet come across for how the brain actually learns and makes predictions. Read it and reflect upon this connection between expectation and perception in lucid dreaming. Perhaps you will notice some similarities in your waking life.
Training yourself to have lucid dreams is not easy. I have had only one lucid experience that I can confirm with any certainty, and it happened without any planning on my part. Apparently, it was triggered by what they call the wake-back-to-bed technique. Fortunately, I keep a notebook by my bed for moments like these, and upon waking, I was able to write down what I observed before the memory of the dream vanished completely. You may find it an interesting study. :)
I had a lucid dream. Or at least, I dreamed that I was having a lucid dream. The experience was considerably less lucid than my true waking state, but it was more lucid than my usual dreaming state. I had this dream after going back to bed after my alarm went off, so I must have had that idea of lucid dream close to mind when I went to sleep.
When the lucid segment began, I was imagining that this was a French king's house, whose cooks were one by one presenting dishes and desserts they had made and were not going to let me eat, me being no guest of the king. But then one of the cooks seemed to recognize me as the king because he let me in and started telling me about all the various dishes he could prepare for me. During this time I was wondering whether I'd be able to taste anything while dreaming, and then managed to conjure up the taste of salami. This was my first lucid act.
Shortly after this, I found myself in my own familiar kitchen, frantically looking at all the digital clocks to test for dream-ness, increasingly ignoring the cook talking to me. Sure enough, the clocks would show drastically different times upon subsequent inspection, with the exception of the microwave time whose dial was being turned and whose numbers were increasing regularly while this motion occurred.
Then I decided to look out the windows and conjure up a lush green setting. It took a moment or two for the view to solidify, but when it did the weather outside was raining hard and the trees were leafy and wet and lush. Sitting on the fence were several turkeys, calling. They may have been vultures. I'm not sure where they came from - I certainly didn't ask for turkeys!
While in the kitchen I found that I had to keep moving my attention, or a sort of blankness of mind would loom where I rested my gaze, threatening to toss me into a new dream devoid of any lucidity. The experience of lucidity in the dream was thus like the experience of being deep in the computer screen, tired, on the web for several hours - I had some capacity for conscious decision-making, but much less than normal.
I don't remember dreaming of falling asleep afterward, but I do remember dreaming that I had woken up. Not that I bothered to go through the experience of finding myself in bed and getting out of it - I just seemed to have hit a switch that told me I was no longer lucid dreaming, and therefore concluded that I must be awake, which I was not.
Eventually, I really did wake up and immediately wrote all this down before I forgot what happened. And so, here we are.
Interestingly, I often find that while dreaming I implicitly understand that I am in a dream, though I only rarely become explicitly conscious of the fact. So if someone in the dream were to say to me, "Are you dreaming?" I would be likely to reply with, "Yes, of course," and then continue on as if nothing unusual had been revealed. About a year earlier I had one dream that illustrates this fairly well. I thought it was rather poetic. :p
At one point in my dream, I was outside on a sort of grassy ridge or hill overlooking a large, dark brown building that had been the focus of the dream events previous. I climbed up onto the top of a chain link fence there, and looked up at the bright, but cloudy and overcast sky. I had an implicit understanding that I was dreaming, but was not particularly conscious of it.
I decided, perhaps to get away from the place that I was in, that I would like to fall towards the sky if I let go, rather than back toward the earth. I knew that since I was dreaming, it would happen that way if I believed it would. So I imagined myself falling up towards the sky and convinced myself that I would do so.
Then I let go, and fell through the sky. It didn't hurt as much as I expected. I'm not sure, but I believe that I ended up in a new dream place then.
Dreams are pretty awesome. They make for a good discussion topic if you want to have a meaningful conversation with someone you don't know very well. Strangely enough, I've found that people are often eager to share their dreams and hear about other people's dream experiences even when they might be bored or uncomfortable discussing other topics.