I turn off work when I leave the building, so I don't check any work accounts from home unless I'm working from home or expect a problem. I've been weaning myself from Facebook at home for a while, and hit it only occasionally on the weekend and during the week. Maybe I can give it up for Lent?
At home, though, StumbleUpon is my weakness. Poof, an hour of my life is gone.
While I appreciate the power of social media, I realize it also keeps me from actually doing things. It's ok to take a break from it. It's a good time to get some exercise or just go outside (even if it's cold outside).