Focus on your breathing. Before you know it, you'll be finished. Play some ball. Use an exercise ball in place of a bench to sit or recline on for exercises such as biceps curls, bench presses, and chest flys. It takes more concentration to keep your balance.
Exercise balls are available at many major sporting goods stores.
Strike up conversations. You may develop some new friendships, which will also make you want to go to the gym. Lift by the tube. Most gyms now have TV's installed in their aerobic training areas. Crank up the tunes.