I workout from home, I started a couple of months ago with cardio to loose some fat, and now I'm starting p90x.
The reason I don't go to the gym isn't because I gave up, it's just I don't like that "all" gym environment, plus the fact that I have to drive there, wait for people to let me use a specific machine etc...
with the money I'd spent on a gym, I'm building my own little private gym.
I can't recommend enough for all of us geeks to workout. I used to drink sugar drinks, eat fat food, all that crap. Even though I wasn't fat I was starting to gain weight and man, I was embarrassed of how out of shape I was.
Look it as hacking your own body ;) make it better, each week you will se improvements, get in shape. Just because we are geeks doesn't mean we can't have a great body for ladies ;P