I would tell the wife and kids that I would drive with my eyes closed and make adjustments at they told me. I would then close my right eye (to my wife's perspective, it looked like my eyes were closed).
The car would gently drift from left to right as it was called out to me to "TURN RIGHT" "TURN LEFT" "GO STRAIGHT". Eventually, I'd pick out a large structure, oh, maybe an overpass or large tree or car parked on the side of the road, and would veer straight for it. Now, don't get all excited. You don't have to be close at all to get the visual out the front window that you're heading towards and object down the road. THEY WOULD FREAK OUT. Then I would "open my eyes" and give them a hard time about almost killing us. Finally, after a few times doing this over several days I told them what I had done.
A buddy and I did this exact thing to his little brother and a girl that was our age in high school. We were on our way to a ball game in Terre Haute and it was probably the funniest time of my life.