This is a silly idea that suddenly came to me. It is a short roleplaying campaign (I suspect 6-8 sessions before it gets boring) that could be played in most systems, with a bit of adjustment.
The players are all ordinary people, working in a fast food restaurant, which just happens to be the most interesting fast food restaurant in the world. Each session basically involves them dealing with some problem or situation, while still trying to do their jobs.
You could run this in most systems, but you need to strip out anything that doesn’t fit with the characters being regular people. In d20 systems, it’s probably a skill cap of 14 and no magic or anything; in Savage Worlds, edges are out, combat skills are out and characters probably have less skill points than normal; in Cypher System, you’d just keep pools, edge and training… maybe descriptors. The point is that these are genuinely ordinary folk.
However, each player may choose a single “roleplaying-y” skill for their character. This might be bolted on at the end or done during creation, depending on the system and the skill. This is the only opportunity for a character to have any combat ability (and it has to be specific; if the character is a black belt, they have no skill in firearms). Alternatively, it could be something more esoteric; the character is a chemistry major and can cook up also sorts of weird stuff in the kitchen; the character knows a lot of people and can acquire anything, given some time; the character is an absolute charmer and can wrap people around their little finger… obviously, if the character has one of these, they have no combat abilities whatsoever.
Your characters all work in a fast food joint. It could be any sort of fast food – I’m picturing burgers personally, but pizza, sushi, whatever… The restaurant should be large enough that there is room for interesting things to happen, but not so large that your players are only a tiny part of the work force – your adventures should ideally take place on the graveyard shift or when the restaurant is short staffed, so that your players are the majority of the employees on site, with only a couple of interesting NPC employees to assist them.
Flesh out the restaurant a little, so that you know what areas it has. Is there one of those windows, so you can see into the kitchen? Is the office at the back or is there an upstairs? Does the restaurant have a basement? However, don’t map every inch of the restaurant, as you want some flexibility during play.
Each games session should cover one shift – any players who can’t make a session are simply not working that day. Every shift, something goes wrong in the restaurant:
The FBI are using it for a sting operation, but they’re short staffed themselves, so some of the characters will need to wear wires.
Two mafia dons have brought their grandchildren in for a treat and mustn’t be allowed to see each other.
Some criminals, fleeing the police, choose your restaurant to hole up and take hostages.
The owner of the company is visiting the restaurant for a surprise inspection, but he’s a bit of a recluse, so no one knows what he looks like… or even if he is definitely a he.
Some guys are filming a documentary about the Indian burial ground underneath the parking lot (this could be a campaign finale, explaining why the restaurant is such a weirdness magnet).
The players have to figure out how to resolve the situation (or just survive it), while still broadly operating as a restaurant (because they need their jobs). This should never be played as a serious campaign, but you’ll still need to agree where you are on a sliding scale of realism; you could play it that the characters need to obey the law, keep the restaurant intact, etc.. or you could play a much more slapstick version where the restaurant is pretty much destroyed at the end of every session, but happily gets rebuilt before the next shift.