I was just letting my mind wander back to high school during anti-drug mind cleansing. We did an "experiment" with little cups of water. Some had a chemical in them that was normally clear but changed to pink when you added something to it. So, everybody wandered around the class and "exchanged liquids" with the others for awhile and them we added the reagent to see who would be pink. Whole thing was supposed to show how fast STDs and junk can spread.
So, just now, it occured to me that while those with the potentially pink juice might infect other people, they couldn't do much of anything to each other. If they knew about their potential pinkness than they might have the opinion of only mixing juices with other pinks.
And that's when the idea for putting an "All HIV Sex Party" into a horror game popped into my head.
It seems like a really frightening concept to a "normal", by which I mean uninfected, person. If you replace "HIV" with whatever strange condition or disease you use in your horror game than it makes for an interesting scene. Give the players someone they have to meet or something they have to get that's located at the party/event and make sure they are made aware of the exact circumstances of the party.
On the one hand, their surrounded by potential enemies, the threat of infestion literally surrounding them. On the other hand, the people involved appear to be actively making an effort not to inject others.
It's a chance to creep your PCs out on more than one level.
I think it'd work best with a horror-investigation game but with a few tweaks the entire thing could be used in alot of different settings. Imagine the party acting as a sort of forced peace agreement between the villain and extremely violence inclined PCs in an action game. The villain will meet them but only at this party, where the people are not only innocent of any crime aside from being ill (and his own guards can hide easily). Any killing will be not only be possibly killing innocent people but also result in the nearly assured infection of the PCs.
So, anyway, I put like five minutes of thought into that. Might be a horrible idea, might offend everyone in the world. If you have offensive ideas for game scenes I urge you to share them as well.