And most importantly... (for those of us with wives and children)

Start coming home from work acting depressed. When your SO asks you about it, explain that there's a big deadline coming up and you're going to have to work at home all weekend. You're going to have to really focus to get everything done by Monday, so you won't be able to take care of the kids this weekend. Oh, and that shopping trip to the outlet mall? Gotta get put on hold. You'll be in the study with door closed...um...concentrating.