I am taking online classes Full Time.
Keeping hand weights at my desk helps me to squeeze in time for toning arms and upper body. I take two 15 minutes at work and I get up from my desk and use the weights to work my tris, bis, shoulders and upper back. I got funny looks at first and then my co-worker joined me and now it's become a normal practice.
So, I just started here at SP. One of the things that my Wife has encouraged me to do is to get a good water bottle and fill it before I go to work and drink from that. A HUGE secret that I've found about myself is that if I have the bottle of water at my desk but off to the side, I will drink very little - like not even touch it. The trick is to keep it in front of me, near my monitor so it's always within view. Instinctivly, I reach for it, take a few sips, put it back.
Create a standing computer desk, or use an existing surface to compute and surf the net from a standing position. You will burn more calories, exercise posture muscles and, in general, promote better health than doing it sitting all the time.