I used to sleepwalk when I was younger, and the creepy part was that I was fully capable of unlocking, opening, and closing a door, before walking down a flight of stairs and looting the kitchen in the middle of the night.
I'd also lock the door on my way back up, so I had [i]no[/i] clue I was doing it until I was told about it.

Oh, and sometimes I'll sit up while asleep, look at people, have a short conversation, then go back to sleep.
One of the times that always gets brought up is once when I did that and my mother was like "Kuro, you're asleep" and my response was apparently a genuinely surprised look on my face, followed by an "Oh, okay then" before laying back down and resuming my snoozin'.

I woke up the next morning to my mother laughing her ass off about it. It was great.