SAD..Seasonal affective disorder.. how do you northern guys deal with it?

I always used to think this was just baloney lazy bullshit. I'm in central Wisconsin.. go to work in the dark, sit in a office with a small window up above my head I can't see out of. Leave in the dark. When I get home, I just want to eat, and go to bed. No ambition. Lots of thoughts during the day..and just no energy to do anything. In the summer, the wife has a hard time getting me to come in by 10 on a weekday, having fun doing stuff. It's almost 8:30 and I'm not in bed yet.. odd for me right now.
Just wondering if any of you get this way in the winter.. and what you do, if anything, to get motivated.