Stanford study finds walking improves creativity
Another great thing about "walking around with a problem" is that it forces you to think before acting -- since you can't act until you get back to your desk. You know those moments when you're in the thick of coding, and you suddenly realize that one detail which you had thought would be easy, is in fact going to force you to rip up a bunch of code? I make it a rule, at that moment, to stand up and go for a walk. Often, by the time I get back, I've found a better solution.