No flames from me for looking at his IM's. My kids won't stand a chance when they're older. DH is self-employed as a computer consultant and just opened a second business with his partner in computer forensics. He can find things on hard drives even after they're deleted and can access all of our computers remotely. I hate when he needs a file on my computer and I'm on it, when the mouse starts moving on it's own.
Our current source of amusement is a night vision close circuit camers we have in their bedroom. We'll lie in bed and watch them play when they're supposed to be sleeping and shout for them to go to sleep. If they try to turn on the closet light, we'll shout out "don't you dare turn on that light and start playing!"
The look on their faces when they look around and try to figure out how we're seeing them is hysterical

. Yes, it's evil and wrong, but consider it the payback for the heck they gave us the first ywo years.