I just finished up our walking diary for 2011 and noticed that our two kids (Kessler and Shaylee; ages 7 & 9) walked almost 2000 miles (3000+ kms) last year. This includes walks to the store, church, school, park, around town and on all of our hikes/climbs.
It sure beats letting them play excessive video games or to veg out in front of the TV or movie theater.
Below, you can see some of the places we walked:
http://www.summitpost.org/2011-trip-log/690759