Way back when the old WEG d6 Star Wars game was due out, but before it actually hit the shelves, I was already planning on buying it (or getting my parents to give me pocket-money to buy it) and running a game: so much in fact, that before I ever had the game in my hands I had written an adventure for it.
I set up the premise– heroes in a ship, passing through an asteroid field, captured by Imperials– and mapped out a space station, as well as an asteroid field and the paths of the patrolling TIE fighters (with numbers representing turns); I wrote up some memorable NPCs, including a Dark Jedi who, in this first adventure, became the heroes nemesis and appeared in numerous adventures as the game went out, suffering defeats and near fatal wounds, becoming a cyborg, but never killed, and the campaign faded away (as many do) before the Rebels ever had a chance to finish him off.
I don’t think that I’ve ever done that since; created an adventure, maps and NPCs, before I ever read the rules or had the books. Sometimes you just get inspired, and the fact that it was Star Wars helped since it was a universe I already knew. Recently, having backed and followed the blog and updates for Monte’s Numenera I have had that same impulse to create something before it comes out (2013). Might not actually get around to doing anything about that impulse, since I have less free time, but it’s nice to have that feeling again.
Has anyone out there in the ethereal sphere of the web ever done this, created an adventure before ever seeing the rules or owning the game system?