It’s not mine – I found it online 3 years ago when I went looking for “car activities for children” before our first 552 interstate journey with 2 preschoolers. It’s worked every year since (“when are we going on a long trip again, Mom?”), and now they count down the mileage between bags on the GPS.
It’s simple, as most great ideas are. Put a treat/toy/activity in a paper sack to hand out to each child every 100 miles.
Here’s our 6-year-old son with a 3D Drawing Pad (note that a lollipop was just as well-received). He’s about 301 miles from home and couldn’t be happier.