On the way to play pinball at TimeWarp in Seattle, I ran into a friend who asked me what I'm doing. I said "about to go play pinball."
He didn't know what pinball was - had never heard of it. (He's in his 50s, so... I don't know why.)
I was stumped by having to develop an improv explanation for someone with no preconceived notion.
"It's um... an arcade game. It's a table with metal balls and flipper paddles in it, and you hit the balls through an obstacle course built into the tabletop. You have to keep hitting the balls to keep them away from a hole where you lose them into the machine. It has music, graphics, and flashing lights. There are many different machines, and they are each designed based on a story - like a movie, or a popular band."
I don't think I communicated very well. I don't think that guy really knows what pinball is based on my description.