My friend Erik Weissengruber runs the superb blog Roll The Bones, which is devoted to his explorations of ludology — the theory of play. A while ago, Erik started designing “concept maps” that graphically illustrate various concepts of gaming. My personal favorite is the enormous, sprawling timeline he created that tracks the development of various theories of chance and luck, as they’re represented in science, philosophy, history, drama, and other arts. The timeline begins in 4000 B.C. (!!) and goes up to 1999 — and includes a zillion swooping arrows showing how ludology developed.

It’s utterly gorgeous and mindbending. It’s kind of like looking inside Erik’s brain, which is an extremely interesting and weird place to be. You can go to his site and download it as an Excel file to read or print up. I visited Erik in Toronto last week, and he gave me the poster-size version, so be warned: This sucker is over six feet tall and two feet wide, and even at those dimensions, it’s so crammed with information that the base font size is only eight points. Hang the history of probability on your wall!