Do you like cycling?
Ride your bike to work. It's a simple way to add exercise into your day.
I was always too lazy to go to the gym, but found cycling was something I enjoyed. So I started doing it more and more, and eventually started riding to/from work.
My office is 18km from home, and the ride takes me about 45-50 minutes. So one day of riding gives me almost two hours of working out, which is great. I do that a few times a week and it really helps. I was never fat, but at one point I was pushing 190 lbs, and at 5'11" I'm a bit short to weigh that much. I'm down to 175 and think it's a much better weight:height ratio.
On the way to work I try and take it easy so I don't get too sweaty, but in the evening I really try and hammer to get a good workout. And when it's light later in the summer I'll make my ride home longer so I can get an even better workout in and enjoy the sunshine and warm weather.