I don't usually remember my dreams for much longer than a few minutes after I wake up. I have had a couple of lucid dreams.
I don't remember the specifics of how it happened, but I realized that I was dreaming, and so I decided to fly. Below were two pine-covered mountains with a river flowing through the valley between them. Every so often was a non-pine tree whose leaves were either gold or red. I kept following the river, and eventually the mountains started to flatten out, but the trees continued. On the right side of the river in the trees, I saw a large black hole/whirlpool type thing in the ground that was sucking in the trees and ground. I flew over towards it, and it sucked me in and I woke up.
In my second lucid dream, I was in a large, long, ground level condo (I've had several other non-lucid dreams at this place). It was dark and cloudy outside, and there was some sort of creature outside. I closed all the blinds so it could get in, but somehow it got in through the entrance stares past the kitchen en at the far end. It looks like some kind of werewolf, with grey fur and many sharp teeth. I looked at it, and thought that such a thing couldn't really exists and realized that It was just a dream. It started rushing at me, so I woke myself up to get away from it.