I have a couple of random stories, but this one still creeps me out the most:
When I was about 12 years old, I woke up in the middle of the night to my cat meowing at my open door. I got up and followed her into the living room - the whole time she kept looking back at me to make sure I was following her. When we got to the living room, she jumped up on the piano which was directly under a large picture window that looked out onto our front yard. As I looked out the window, I watched a round object, about the size of a basketball, slowly float down my driveway about 4 feet off the ground. It got to the end of our fence and went toward our neighbor's house.
It had a couple of tiny lights on it. It was dark gray. I stood there for a minute with goosebumps on my arms, then walked back to bed. I know this was not a dream, and my 12 year old mind definitely did not make this up. It has been burned into my mind for 18 years, and I have no idea what the hell I saw.