I used to do something similar. Luckily, I had a cube at the end that faced a wall. After I started feeling some wrist pains I set up a keyboard-timer, a program that was part of Gnome that locked the screen after a given interval of continuous activity. I set it to 2 minutes every 30 minutes that didn't include at least a 1 minute break from typing. During my 2 minute break I had enough time to do a set of push-ups and a set of sit-ups and would alternately go refill my water and go to the restroom. I think it ended up being akin to the Pomodoro technique because I found myself working harder and really getting into the zone to beat the timer.
I also had a period where I bought a new car and started driving to work. I put on about 15 pounds over two months. I realized this and went back to biking to and from work. For me, bicycle commuting is the best way to get exercise because it doesn't feel like wasted time when I would just be sitting in traffic anyway. It can be a bit of a hassle, but I get to comfort myself with monetary savings and benefiting the environment.
Bikes are awesome. I just moved from a college town to a big city for summer internship and I'm toying with the idea of buying a second hand bike for the duration (cheaper than public transit?) but this city doesn't have the same ubiquitous bike-rack infrastructure as the college town, so I'm not sure where I'd park it...
I also had a period where I bought a new car and started driving to work. I put on about 15 pounds over two months. I realized this and went back to biking to and from work. For me, bicycle commuting is the best way to get exercise because it doesn't feel like wasted time when I would just be sitting in traffic anyway. It can be a bit of a hassle, but I get to comfort myself with monetary savings and benefiting the environment.