Random selections from noisms' Great Book of Game Ideas Which Will Never Take Off:
Catalogue 34c, book III, chapter 87, subsection IX, no. 679: A story-games.com style game based on the Harlan Ellison short story I Have No Mouth And I Must Scream. Four to six players are trapped inside a planet sized Artifical Intelligence whose only motivation is its pitiless hatred of them. Over the course of the campaign they are tortured and brutalised in ever more inventive ways, the only stipulation being that AM (the AI) cannot allow them to die. There is no GM - the players each take turns 'being' AM, with the challenge being to trump the previous guy.
Catalogue 11a, book LXII, chapter 18, subsection XXV, no. 81: A Cyberpunk 2020 game set in Equatorial Guinea, where vast oil resources are the focus for clandestine warfare between megacorporations, the government, other African governments, power-crazed mercenary bosses turned warlords, and shining path style maoist rebels. Like the Wild West except on the equator. In Africa. In the Jungle. With railguns.
Catalogue 42j, book X, chapter 119, subsection I, no. 70: A hybrid of Spelljammer and Star Trek: Voyager using Risus. A spelljammer ship becomes stranded hundreds of years away from home by some vagary in the phlogiston, surrounded by weird alien races and desparate for coffee. No Janeway, though.
Catalogue 87d, book V, chapter 1, subsection IIX, no. 6: A MERP game set in the early Third Age of Middle Earth. A group of adventurers set off from Rivendell into the East, in search of the 'blue wizards'. They encounter a corrupt magocracy in the vast, sparsely populated barren wastelands and mountains, and must fight an unrecognised and thankless battle against it in tandem with greater events back West.
Catalogue 14p, book I, chapter 73, subsection XXVII, no. 33: A Risus game set in the Mesopotamia of the Book of Judges, the Epic of Gilgamesh, and ancient Sumer. The players are demigods with stats like "Donkey-Jaw-Bone-Wielding Genocidaire 4" or "Shagger of Thousands of Other Men's Wives 2", and they battle against mountain-sized giants and other legendary monsters.
Catalogue 48x, book LI, chapter 9, subsection IV, no. 189: A campaign set in a mystical version of Kofun-era Japan. The players are a group of rational and well educated Chinese diplomats who are trying to find the Queen of Yamato's court, in an archipelago full of mountains, forests, barbaric tribesmen, dragons, oni, tengu and river ghosts.