There's a story I heard years ago. One that I've sunk far too much time into finding the original source of without success. I've always wanted to share it, so why not now.
Wargames have been around for centuries. H. G. Wells was an advocate of miniature wargaming and even published a set of rules for it. Before wargames found any sort of recognisable popularity and the player base was sparse, people would play-by-mail. Each player would take turns sending their moves to the other, much like in a game of play-by-mail chess.
Half of the battle would be finding someone in the first place to play against, so people would advertise in newspapers that they wanted to start a campaign. Unfortunately, much like children playing in the park, everyone wants to be the hero and no one wants to be the villain. This is of course where people got creative and a few savvy players, when writing their newspaper adverts, would take on the persona of a Axis General, making bold and highly inappropriate statements to provoke the Allied players into starting games with them. This was met with great success and thus started one of the earliest forms of role-playing in a wargaming setting.
It would be a little while before Gary Gygax would help this evolved into Dungeons and Dragons, but it's pretty neat to think about.