One of Theo's more annoying misbehaving behaviors is his need to pull towels down off the towel racks. I'll get home some evenings to find all my towels lying on the floor. Diego is part culprit as well but from my observations Theo is the one usually to blame.
Rather than try to think of a punishment for this behavior (punishing him way after the fact probably wouldn't be too effective) I decided instead to assign Theo the duty of making sure the towels are nicely hung when I get home. I don't care if he wants to yank them down when I'm not around, I just don't want to see any evidence of this.
So for the past couple of weeks when I get home, I walk to the upstairs and main level bathrooms with Theo, peer in and praise him if he's done his job. I'm sure he doesn't understand the lavish praise but it's been a while since I've found my towels lying on the floor.