I was nudged towards this by Fiction Related, and hey, I'm a sucker for this kind of thing.
Day 1: First RPG Played
I'm 99.9% sure that this was something called After Sundown. It's a heartbreaker World of Darkness adaptation that some friends offered to playtest. We ran it as a high school story where our gang had a rivalry with Zombie High, and my amiable jock golem ended up stealing their brain-in-a-jar mascot, adopting her and teaching her to play Halo. Then we fell into an alternate dimension where everything was broken, and killed a powerful demon or whatever it was. This turned out to be a prank by someone we'd ticked off at school. It was pretty fun, but there were a ton of issues with it.