Back in the day, the odometers on cars used to actually be a series of dials. As the lower dials rolled past nine back to zero, the dial to the left would increment one as well. This became more fun when you ‘rolled it’ or went from 99999.9 to 00000.0 (as they didn’t show hundreds of thousands). I remember seeing it happen a few times from when I was a youth and it always left an impression on me.
So on the old car, when we came close to rolling the odometer, we piled the kids in the backseat and drove around the Safeway parking lot a bit until it rolled over so they could see.
With the van, I recently ‘rolled it’ from 199,000 to 200,000.
With the new digital odometers, it’s not nearly as cool.