David Ahl’s BASIC Computer Games (1978): I actually have a copy of this book in paper, dug up in some used book store pile ages ago, but now, you can revel in its full glories online.
Before there were sprites and polygons and first-person-shooters, before there were CRTs on every desk to splash graphics in our eyes, there were simply teletypes chattering out lines of text. And there were paper tapes for you to store your work. Right around the time Richard Nixon was being kicked out of office, I was learning BASIC by reading the code to some of these games. (We didn’t get them from the book — they were just floating around on the minicomputer we timeshared.) “Hammurabi,” a sort of primitive, text-only SimCity, was the one I and my circle of friends latched onto — and proceeded to amend. Because all these programs were free and, in the manner of their time, open source. [Thanks, Boing Boing and Oblomovka]