I stopped going to the gym ages ago. Instead I get my exercise by taking part in many activities which are much more real.

Long walks with my wife. I'm a member of the local 'outdoor club' which does a lot of hikes, backpack weight training, stair running, bike riding, climbing, camping, and other active events that I can take part in with others...much more motivational than sitting on a treadmill plugged into an iPod. I also walk to and/or from work whenever I can.

It's not what anybody would consider 'hard core' or anything but it's consistent and it's regular and that's the key thing for me...it's easy to get in a rut of not doing anything...and anything is better than nothing.