Let's go for a permadeath RPG. You're given a world to explore and a randomly generated character with which to explore it. The world would be a fantastic post-apocalyptic mishmash of magic, aliens, demons, pockets of advanced technology, and so on, so there's a very wide range of things your character might encounter, and each encounter runs the risk of permanently changing your character.

At the most basic level, any battle runs the risk of wounding your character, and wounds wouldn't be a simple matter of a number of hit points. The game would keep track of the bodies of all the people in the game, so any injury would be an injury to a particular body part, and different injuries would have different effects. Limbs could be severed, or they could be infected by a wide variety of things. Amputations would be an option to deal with certain problems.

On the other side, some encounters might provide new limbs, such as electronic prosthetics to replace lost limbs, or provide extra limbs. Magical encounters might also cause new limbs to grow, or change the character's body in even more drastic ways, such as becoming a centaur, or a giant, or a cyclops.

Whatever happens, the game would encourage the players to always continue forward, never reloading a previous save, because undoing negative results would destroy the challenge and thrill of exploration. When your character dies you would continue with a new character, though each new character will start in a random part of the world. Even when you start fresh with a new character, you still gain progress by remembering the things you found while playing previous characters in the same world, making it easier to find positive things and avoid negative things.

The goal of the game would be to gain skills, abilities, and magic powers through exploration and encountering the wild people and places of the world, and then use those powers to reshape the political situation in the world to your liking, most likely by killing some sort of evil tyrant who is threatening the world's peace.

In addition to going on adventures, there would also be tools provided for designing and sharing custom worlds by drawing maps and populating those maps. By sharing worlds, a player need never run out of crazy places to explore.