My Wife’s Grandma and Mark Twain: A Freakonomics Quiz

My last quiz on horse racing was hard: you needed to know some institutional details, and even if you did, it was still very tricky.

This next quiz is quite easy. For a piece of Freakonomics schwag, just be the first one to correctly answer the following question:

What do my wife Jeannette’s grandmother and Mark Twain have in common?

(Note: I’m sure they have many things in common, but there is one in particular that I am looking for.)