As a parent it can be difficult to find time and energy for a workout. Even if you can't manage a gym membership, you can walk. Walking is the best exercise for your health, energy, longevity, appearance and emotional well-being even if it's only 30 minutes a day. Take those kids along with you. Children need to develop the habit early, even if they aren't walking yet or able to keep the pace.
Kids may be an excuse not to exercise, when they're a reason why you should.