There's a thing often called polyphasic sleep, where you condition your brain to enter deep sleep as soon as you fall asleep. To do this, you get to sleep 20 minutes every 3 hours (there are different techniques). That means less than 3 hours of sleep per day. Image what you could do with 4 or 5 more productive hours in your days (for years!). Of course if you have a regular job or are a student, you probably can't do it. Also it's supposed to be very hard at first because you are not conditioned to have good sleep as soon as you hit the pillow. Animals do that all the time.
HOWEVER, there might be drawbacks. I'm no expert on sleep and it's possible that it is not so good for your health. If you really want to try that (I haven't), search on the internet beforehand.
I once read a blog about a a guy who was doing this, and he said that his dreams were just like reality, much more vivid than normal dreams. Lucid dreaming is another interesting subject. When dreaming, you have to realize that you are dreaming (without waking up!), and then there are tips and tricks to modify the dream to whatever you want. Yes, anything.
I remember reading that you should get the habit of checking your watch twice. That way, you get this habit in your dreams too and if the watch doesn't display the same time twice, it means that you are dreaming. Also, when you realize that you are dreaming and want to be someplace else, all you got to do is a complete spin and the scenery will be totally different.
I guess that'd be fun, but I don't even remember most of my dreams.
