Day 1: I once read that if adults tried to mimic -- move for move -- a mobile baby's actions in a 24-hour period, they wouldn't be able to do it. (I have no idea if that's true.) It seems hard to believe, though, considering that there are people out there who climb mountains, run marathons, and ... you know ... Lance Armstrong.

Still, after I read that, I sat back and watched my then nine-month-old for a good 20 minutes. That's when I learned what everyone else already knew ... kids are BUSY. I think in that short little time period, she crawled a baby mile, pulled herself up to a dozen different things, and climbed our staircase twice.

My kids are older now, but no less active. They're certainly getting enough exercise every day, so now it's time to find out if keeping up with them gets my heart pumping too.