Knowing that my body is built to work, it was not built to be lazy and do nothing. I'm a mom of 2 kids now that keep me busy and I need to be able to keep up with them. They get me out of bed to get with it!
I agree with Tiffany. I have to keep up with my kids. Plus exercise is one part of my day (one of the few) that is just for me... although my kids reap the benefits of this time by gaining an energetic, stress-free momma. :) I also know that by setting a good example of fitness, I'm setting them up to be fitter in their lives too. That's pretty motivating for me too.