I used to watch my daughter at night on the video monitor when she was a wee one. As she outgrew her crib, we moved her to a toddler bed. We put up a gate/fence thingie that pretty much bisected her room. One half was her sleeping area, the other was her room and play area. She would play us all at night: She could hear when we were coming up the stairs, and would feign sleep. I mean, we'd lean over and kiss her goodnight, and she'd be seemingly out cold. As soon as she heard the door close, you'd see her head pop up, look around, and then she'd climb off of her bed. She would move things over to the gate area and stack them so she could climb over to go out and play. She'd then reach through and lift her "steps" over to the outside so she could get back in again when she was done playing. Once inside, she would put everything away like it was never disturbed, get back in bed, and go to sleep. We knew this was wrong, but could only watch in amazement the first few times.
Shit, I wish I could get her to clean her room like that again NOW!