Bill Casselman is interested in the history of the number 0, and travelled to Gwalior, India, to see one of the oldest known written occurrences of it. I had the good fortune to be eating at a dinner with him in which he was talking about his trip (see http://www.ams.org/samplings/feature-column/fcarc-india-zero), and another diner remarked, without missing a beat, "that's a long way to go for nothing."