When I was in high school back in the mid to late 1990s (between 1996 and 2000), my friends and I play-tested a fantasy role-playing game that one of them had received through the mail. The main conceit of the game was that you (the player) was pulled into a medieval fantasy world with nothing more than the clothes you were wearing right now and whatever was in your pockets. You made characters based on your real-life stats and skills. I don't remember much about the system itself. It may have been percentile based, but I also seem to recall that there were basic stats similar to D&D (Strength, Constitution, Charisma, etc.)
I don't know if it actually became a published product or not. It was definitely a separate system, rather than an adventure for another system.