Nobody really takes this story seriously since it happened when I was around 6 years old, and my sister would have been 5. However, it's one of the most vivid memories I have, recent or not.
Just to set the scene a bit: Being Friday in the 90's, my family's tradition was to go down to the basement and watch TGIF together. That night, my little sister and I decided to head down before everyone else. At the time, my older sister must have been in her room, and I know that my parents were in theirs. At the end of the hall to the left is an open door leading to our powder room. The basement stairs are to the right of the end of the hall. For some reason, none of the lights were on at the time.
So, my little sister and I walk together down the hall to the basement. Once we got to the end of the hall and were about to turn to go downstairs, this milky, translucent figure comes gliding out of the bathroom, right by us, and shoots down the basement stairs, makes a quick turn to the left once it got down there, and then disappeared as it continued on. My sister and I both started screaming at the top of our lungs, and ran as fast as we could upstairs to my parents. We were both absolutely hysterical. I distinctly remember this as the only moment I've been too scared to even form a sentence out loud. I couldn't process what I had just seen, it was just too unbelievable. We managed to explain that we had just seen a ghost, but my parents didn't really understand what was going on.
They separated us into different rooms, and got us to draw what we saw. We both drew shockingly similar pictures - a tall man wearing a long coat and a top hat. People have tried to come up with different theories as to how such an image could have been projected into the darkness that night, but none of them really make sense to me. This image was so clear, so crisp, that it couldn't have been a reflection, refraction, or a shadow. It was a translucent person, travelling swiftly through the air.
I sometimes try to convince myself that I don't believe in ghosts, but I still can't shake the vivid memory from that night. Unlike my sister though, I've been more or less able to keep it engraved in my memory as an image, and not let it get to my psyche. When I think about it in depth like I have just now, though, I get a shiver down my spine that doesn't go away until I distract myself. Thinking about it still gives me the creeps to this day.