Sleep Playing?

At about 5:00 this morning I woke up to
"Scrrrrrrrrrrrreeeeeeeeeeeeeeeeeeeeeeeeech!"
Followed by the sound of a couple of very small feet running a very short distance above my head. Then it was silent. I turned on the baby monitor and couldn't tell what was what so I headed upstairs to find her sprawled out on her stomach in the middle of her floor...asleep. There were baskets of "mittens" and pajamas strewn about. Did I miss something? Had she been playing so hard that she finally conked out and I just heard the last of it? Or did what I imagine took place really happen? I imagine that the baskets and such happened at another, much earlier time during the night and what I heard at 5:00 am was her getting out of bed, screeching, running and then literally "falling" back to sleep. Hmmm. Is there such a thing as sleep playing?