I'm seeing a small trend towards using Standing Desks, to encourage fitness. For example, Gina Trapani (of Lifehacker fame) who has written about it at Why and How I Switched to a Standing Desk. Here's an excerpt:

My workday—which consists almost entirely of typing on or talking into a computer—is completely sedentary, and is a big part of the reason I'm more than 20 pounds overweight. Burning more calories while I work is a better use of that time.

Why use a standing desk?

Two reasons: Higher calorie burn and better posture. When I'm sitting at my desk, even in a fancy ergonomic chair, I tend to slump, with my back curved and shoulders forward, which closes my chest and makes my breathing more shallow. When standing at a desk where my forearms are at a 90 degree angle on the desk surface, my shoulders go back, which makes my spine concave and opens my chest. Besides the initial foot pain and muscle aches of engaged thighs and calves, it feels great.

I didn't discuss the switch to a standing desk with my doctor, though there have been some studies about the negative health effects of excessive sitting. I'm not a medical professional, but it seems obvious that human beings aren't meant to spend 45 hours a week sitting still in a chair. Now that I'm standing, I pace, dance, and fidget a lot more freely, which is just more natural activity and calorie burn built into my day.