Since I have two small kids that keep me busy, I try to run around with them at the playground, while occasionally doing sets of pull-ups and dips. I just basically act like a kid myself and it seems to be helping because I am in better shape recently..I also keep two 25 lb dumbells right by my night stand, so I can just grab them and workout when I have the time/energy. Sounds funny, but with my work schedule and my kids, I have to squeeze 3-4 small workouts in each week for a couple hundred reps of shoulder presses, lunges, etc.