Sneaking in Fitness
If your children are a bit older, let them help you clean the house. You can burn about 100 calories during a 30 minute chore like mopping or scrubbing the tub. This activity comes with more than one bonus.The house gets clean (for a little bit, at least), you're getting some exercise, and you're teaching your children the importance of chores. Kids especially love things they can play at, like washing the car. Just don't expect it to be streak-free when all is said and done.
Just remember, not everything happens in a day. The house will probably never be fully clean with kids around. You can only do so many crunches before your tummy gives out. Enjoy your little ones and consider everything a work in progress.