Day 12: Old RPG you still play / read
I'm not sure if the intention is "RPG written a long time ago" or "RPG bought early in your gaming career". Mine is fairly short and compact so there's not a huge amount of difference between my early and recent purchases. Oldest in age is, still, AD&D 2nd edition. Earliest bought is 4E D&D, which I still run when those folks want to game.