If you really want to show that you're not in the 21st century have the kids leave the house unsupervised to go play with friends

Sun's up? GO OUTSIDE. Late in the day? Make sure you're near home. Street lights just came on? Listen to see if mom's yelling for you to come home yet.

I used to bike all over the place with my friends, and by the time I was 10, some of those trips were long. And we didn't have cell phones.

The world's a lot safer than you think, it's today's generation doesn't exist because the previous one's kids all got abducted and murdered. Still, my kids have phones instead of a quarter in their pocket and instructions to look for a payphone if they need me.