Here's one no one but the Koopman's can relate to: holes. You know, those things you put on pieces of paper that have a 3 hole punch to reinforce the holes? We just call them holes. One year when I guess I was around high school age I got a pack of them as a stocking stuffer and decided to make a huge deal out of it, like it was the best gift anyone could ever give. Since then holes became a staple of the Koopman family Christmas.
Holes.