You can find a ton of links and resources if you do a quick search on google, yahoo, etc. Basically it is when you realize that you are dreaming and become conscious enough in it that you can play a more active role in what you are doing. That's my simple definition. Usually these dreams are extremely vivid too.
Mkc414 did a pretty good job of explaining it. Its pretty much where you realize "wow im in a dream" then you have the ability to do pretty much whatever you want. You think its reality, when you wake up your pretty dissipointed it didnt acctually happen, or maybe that was just in my case.
ya lucid dreaming is awesome... imagine a dream, but where you control yourself in it... YOU decide what to do in it pretty much.. and ye know youre in the dream land somewhere in the astral plane. when u gain lucidity its tough to keep it for a long time, usually you stay lucid for short periods of time, but something i realised that helps keep the lucidity longer is to meditate in your lucid dream... just stand still... the clarity will come back.
oh, i used to get that alot when i was younger but it would end like a 30sec after i realise. now to think of it i havent had a 'lucid' dream in maybe 6 months and that sucks balls
the only dreams i tend to remember are somewhat lucid in my control of action but i forget its a dream usually and just go along with all the wierd shit as if its real, and i have to engage it. but yeh i cant really think of any other sort of dream other than one where im wandering around looking at wierd shit or going through some sort of story. the thing i cant control is my setting and the things that pop out around me. i often end the dream when i do something that should kill me (however - usually it is not instant, but a second after i should have died when i stop and realise definately 'hang on - this is all a dream after all!' and then wake up. ugh but often i like the fact that i think its real. because i still think 'real' includes all the wacky things that go on and its really entertaining. i think i learn a lot about myself and ways to act in the future, in dreams.
>you realize that you are dreaming and become conscious enough in it that you can play a more active role in what you are doing >>I lucid dream all the time. Imagine make believe world a.k.a. dreamland, next relize you are asleep, after which pretend in your dream. Now you are lucid dreaming. The more you do it, the easier it becomes -seriously!