I’m really new to LDs, and I find it all very interesting, something I’d like to achieve myself. But, I’d like to know it’s potential first, and other such cool things about it.
So what was the coolest thing you could do in a LD? Also, in lucid dreams, can you control EVERY aspect, like your surroundings, or just your own actions?
Hi
How much control you have depends on you.I think it is possible to have full control , but difficult (and boring).
Most people can control their own actions, and can “influence” the dream.
For example, you want something to eat.
Now you concentrate on the thought “I want something to eat”
Perhaps that will work, but you can´t tell wether there is suddenly a pizza in your hand, or wether you turn around and what was your house before is now suddenly a grocery store.
Same with flying, some people can fly very easily, others just can´t cause their subcounciousness doesn´t accept that there is no gravity.
So, it is hard to tell what you will be able to do in your lucid dreams.But:
Traumgänger
I agree that it can be more exciting if you don’t control everything.
Letting your mind randomly generate people and places to explore is the more satisfying part for me. However, with enough practice it is within your ability to shape the entire world to your liking. You can go anywhere you want, familiar or not, and create people you want to interact with.
The general rule is, if you can imagine it when awake, then you can live it when asleep 
Doesn’t this belong into “the Quest for Lucidity”
Oh well 
no. The title makes it seems so, the content does not.
It’s potential is only limited by your creativity and imagination. You can control most every aspect, it just takes some practice. You need to find a technique for everything. Someone suggest using a magic wand, that should work great. Just wave the magic wand to make it rain, or turn someone into a toad. Or you can also imagine using telekinesis like I have, then you can move stuff like it is an extension to your arm. Changing scenery can be as easy as walking to another room, in dreams a theme park can be in your bedroom closet. 
My best lucid dream will be the one in which I actually manage to stay lucid! 
‘could’ is a bad word to use. In lucid dreams only your will and imagination border the limit to your potential, since you have no physical bondaries like physical existence holding you back.
I don’t meditate, I excersize and analyze, and I’m sure my lucid dreams differ from someone that meditates and controls his mental reality in the physical world, for example.
To read more on how the outside world influences our potential read my “sovereign reality” post in the “Beyond Dreaming” forum.
Speaking of letting your brain do most of the work in your lucid dreams, in my most powerful LD I walked through this house… down some stairs and out onto the little stoop in front. The house sat right on a little suburban street, the yard only about three feet of dirt in front of the sidewalk. There were trees lining the street and sunlight was coming down through them and shinning through the leaves…
It was a normal scene but it was gorgeous… felt like home. I think I prefer leaving the setting up to my brain most of the time. I think its possible to control exactly where you want to go but I prefer to give vague suggestions like… “space” or “the beach” and see what my head comes up with. 
My second LD was spent looking at the night sky.The moon was huge,and moving my hand back forth across the night sky would cause bright comets to cross the sky.This lasted for about 15 seconds sadly.
Usually my dreams just seem to stop once I become lucid,so I can usually only control my own actions.The one above was the only one for me where the environment moved a little.
I’m pretty sure as you have more LDs you have more control over your dream world and what you want to do.You can do anything you want in an LD,but it’s like playing an instrument or riding a skateboard for the first time.The possibilities go on and on with what you can do with them,but it takes interest and yes,practice.
Cool things to do while lucid (I can vouch for all of these):
Fly. I know it sounds very new agey (“wow man I can fly!”) but flying at high speeds in an ld is a breathtaking experience.
Sex. Realistic, you choose your partner/s. What more can I say!
Look at what your subconscious has created. Especially the sky, landmarks etc.
Talk to dream characters. If you know them in real life try to remember they are only your dream-version! (very hard to do: I once made my friend ‘lucid’ in the dream and exchanged passwords for when we woke up! I dont think this counts as a loss of lucidity though… i genuinlly thought he was ‘there’ in my dream!)
Go for a WILD! Regular lucid dreams are incredible but an Out of Body Experience is even better. I have less experience with WILD but they are clearly the ‘highest’ level of ld.
Stay lucid for long periods. Waking up after what felt like 20 minutes of lucidity is great.
As for my favourite lucid dream, I posted it on the Dream Diary page. Its back on Page 4 and titled “Who turned out the sun?”
My best LD was last night, when I was flying! You have GOT to try that it is SO COOL! 
Just thinking about it makes me feel like I could fly right now. Wait a minute…jumps up and down while waving arms frantically in the air…nope, not a dream. Too bad…
PsychicHawk28, I couldn’t agree more. One of my favourite things is definately flying over a strange un-earthly landscape at night. It’s just so amazing.
Other than that, I enjoy exploring my house, and the streets in the immediate area. I guess I just love exploring the strange environments that my mind creates for me.
One of my most memorable LD’s was when I turned lucid, I heard a song I had written playing loudly. I could change the instruments that were playing it at will. All this was happening while I was looking at an incredible vista - there where small buildings dotted over a hill, with loads of sunlight everywhere. I then saw a massive beanbag up in the sky so I flew up to it and landed in a recess in the top and floated back down with it.
lol same here
just to clear something up, in a lucid dream, if you are really lucid, you can control any aspect. On my first lucid dream I had a boring setting, I decided to appear in an airplane in the middle of a storm. i didnt have to think about the details of the airplane. i basically thought “i wanna be in an airplane” and then my mind did everything for me and created a nice realistic and freaky shaking airplane. you can also make people appear. i made a whole bunch of pretty girls appear in the airplane. Though, sometimes its not that easy to make things appear, you just have to imagine them appearing. If you try hard to make something appear, you might lose lucidity. another thing ive noticed is that in lucid dreams, i lose many of my real-life fears. one thing to keep in mind, lucid dream in a place where nobody will bug you or your sister will come and scream “wake up, you got to take a look at the worm I found!” as it happened to me.
good luc
Actually, Lucidity does mean being in complete control. It refers only to being consious in your dreams.
There are different stages of lucidity. You are talking about absolute lucidity above. Beside that there is
Hi
The best thing I did till know was flying over the town where I live, at a sunny day with blue sky, flying past the big church, watching down at the field tha surround the town…
And I didn´t even intend to do so, I just used flying as a way to get from one point to another point (to the “lucid crossroads”)
Traumgänger
I mostly just get low level LDs… at least lately. Its getting a little frustrating but I know I will prevail. Im getting LDs more frequently the more I have them and thats good.
I actually find sex frustrating in LDs and its usually a sign that I am not as lucid as I want to be. You see, I would MUCH rather be doing so many other things but it seems that when I am only in a low level LD I just revert to doing that one thing in a semi-conscious way. It sucks ass. I always wake up feeling stupid for wasting my time doing something I could do in real life. 
I would much rather explore and take in all my senses, fly, play, talk to characters…