Mostly I come to these forums. Occasionally I go brew some coffee, or sit on the toilet and play smartphone games.
I'm pretty good about doing none of these things when I have a deadline though.
Oh, when I'm working from home, I sometimes take an hour off to take a long bath and read a book, or play a game briefly, and I always have Netflix on in the background.
Despite this, I'm far more productive working from home. Netflix is a surprisingly good productivity tool for me.