When I was in third grade, I was invited to a sleep-over at my (then) best friend's house. Spending the night there was normal to me. I spent the night almost every weekend, so going there wasn't a big deal. Looking back though, I have to admit that that house was kind of creepy. It was small, but I always felt someone was watching me all the time, especially when I was alone or if I was the only one awake.
Anyways, I went to the sleep-over, which had about four or five other girls. After having a lot of fun, we all settled down to sleep in the living room. I remember waking up really late into the night. Probably around two or three o'clock. I was sleeping on the couch and adjacent to me, in the opposite corner, was the TV and a set of speakers that stood on each side of the TV. I looked at the speaker on the right side and saw a girl looking at me. From what I remember, the girl was singing some song. She looked about 12ish. I remember seeing her in like a brownish/sepia color, like the type of filter you can use on a picture when editing it.
She was dressed in an old-time 1800s dress, like the ones the Ingalls girls wear on "Little House on the Prairie". Her hair looked blonde (though it was a little hard to tell due to the sepia color) and was in pig-tails. Her song sounded like a nursery rhyme, but one that I didn't know and I couldn't understand what she was saying. Then, as I was staring at her scared shiatless, she and her song slowly faded away.
The next morning I asked my friend and the other girls about it and said that they were all asleep and didn't see anything. It still kind of creeps me out a little bit...