Where there's a will, there's a way.

At first I was known as that pushup guy at the office, then all the guys did it with me. It was almost a joke. "Alright, it's pushup time!" and my group did pushups. We even got a pullup bar installed. Some people preferred to take those times to walk a lap outside.

If we're going to generalize about what can/can't be done at a software developer job, punctuating the job with some brief exercise is in the "can" camp.