I have a few ideas that I will almost certainly never develop. If someone wants to use them, please do. These are games I wish existed.
Here they are:
The first one is a game where you play as Mormons, and the goal of the game is to be nice to people no matter the cost. It would start out with fairly easy things, but then you come across increasingly hostile or dangerous circumstances where you have to choose between negotiation or fleeing. You can't "die" in the game because, if you are about to die, either God or the angel Moroni will intervene. At that point, you must restart a mission. Then again, I'm not that opposed to the player dying either. I know not that much about Mormonism other than that I've known Mormons throughout my life. :)
Another idea I have is for a game I call "Monkey Town". It's somewhere between Sim City and The Sims, and takes place in a world where monkeys and various apes take the place of humans. They are as intelligent as present-day humans, but they do thinks in their own monkey ways. You are the mayor of Monkey Town, and you must build it up and maintain it. There are problems you have to deal with like monkeys pooping everywhere, political corruption, ape speciesism, infrastructure failures, monkeys rioting, monkey insurrections, etc. The monkey culture would have some differences from human society like knoodling being allowed in public, networks of vines are used for monkeys to swing between neighborhoods, bananas as currency, and so on.
My third idea is a game called "Shut Me Up", which I think of as more of a short arcade style game where your job as the player is to harass and scream at people so those people start telling you to shut up. But you keep doing it so that they start physically attacking you to get you to shut up.