Short version:
I had one.

Long version:
I had one. It was followed by SP, which was freaky because I had no idea what it was. I experienced SP sporadically afterwards, and eventually I found out what it was after someone else mentioned it somewhere. I read a bit about SP, and about LD because it's a closely related topc, but I didn't really do anything with this information other than think "Oh, cool, so I'm not going crazy, and there isn't something physically wrong with me." Later, I decided that dreams were important, and it bothered me to forget them, so I started keeping a dream journal. Then I remembered I'd read that a dream journal was a good first step to lucid dreaming, so I decided, hey, why not take that second step since I'm already taking the first? And that's how I ended up here.