Can't make it to the gym because you're busy with children? Easy! My son loves helping me workout. What seems like a fun game to him is an intense workout for me that we both enjoy. Long story short, kids make great weight plates!
Chest workout? Give them a shoulder ride while you do pushups. Biceps? Lay them in your arms for curls. Squats, lunges, a shoulder press, etc... Use your imagination and you can get a great workout if nearly every body part and your kids will likely enjoy this new game. Which is good because they will beg to play it, which in turn keeps you from skipping your workouts.
Any other parents have any creative child exercises?