I absolutely sympathize with all of us office drones looking to stay in shape. I know in the first few months of my desk job I gained weight without even knowing about it , and then I found out the hard way - when my pants didn't fit. I work at an office where it's rare to work 8 hours and more likely to work 10+ because of the work volume, so I know what you mean about it being hard to squeeze time in.
I've been lucky in that I found an option that I actually enjoy enough to motivate myself to go even after a long day at work - Zumba. I absolutely love Zumba, and the class I go to two nights a week is on the way home, so I have no excuse. I put my workout stuff in my car the day before so I can't forget it, and every Tuesday and Thursday I make myself go. And I never ever regret it! In fact, I'm sad on days I have to miss it. So that's just one suggestion to add to the many good ones above - find a workout you like so much that you'll want to make the time for it.
Rose Tyler - Doctor Who
River Song - Doctor Who
Kaylee Frye - Firefly
Fem!Sam - Supernatural
Sam Winchester - Supernatural
Fem!Sherlock - BBC Sherlock
Fem!Newt Geiszler - Pacific Rim