Take a break... Although sometimes it's hard to I usually try to get away from the PC. Go for a walk or run. If you're feeling really worn out try and take a weekend away. Get back to nature... Do something different...
I walk around in my rooms and talk to my family. Although my fren keeps me always relieved from work because both of keep on chatting during that. Also I listen music which keeps that burnt sort of feeling far far far away from me. So I guess I have many sources of regeneration. And ya one more thing< I also hang out sometimes with my frens for a longer time to give some break to my work.