D&D Earth
Players start in a fantastical version of China at the beginning of the 13th Century. The world has no humans dominating everything so each culture is represented by a different group of humanoids (taking a cue from
Eberron, I ignore the alignments from the
Monster Manual). Southern China is ruled by the hobgoblins, northern China by bugbears from Manchuria, and Mongolia is home to the goblin tribes. Using
Fantasy Saga rules.
Stargate: Faerun
In Victorian era England we discovered a portal to another world (looks like the one in the
Stargate movie). On the other side of the gateway lies a post-apocalypse
Forgotten Realms. Imagine it's like exploring the jungles of South America and finding mythical creatures (i.e.
Dungeons & Dragons monsters). Lots of ruins to explore which have been mostly reclaimed by nature. Using
E6 rules.
Project: Force
Top Secret/S.I. or Ninjas & Superspies in modern times facing communists and terrorists. The wrinkle is, what would the modern world look like if The Force (as presented in
Star Wars) existed and was known by a few. No jedi order, no spaceships, no lightsabers, and no blasters. Think James Bond or perhaps I'd turn back the clock to World War II. Using
Star Wars Saga Edition rules.
Marines in Space
A spaceship folds space, crashes on earth, no aliens survive, and years later in 1980 the technology is found an exploited by humans. By 2000 space travel is mainstream. In the near future we figure out fold-space technology and travel instantly to other solar systems or so we think. The Theory of Relativity has some issues with
faster-than-light travel and my wife is a physicist so I created this campaign to appease her. Instead of traveling across the galaxy, fold-space movement instead shifts the vehicle to parallel dimensions. Nearby parallel dimensions are so similar to ours that it is almost impossible to tell from star charts that you haven't crossed great distances. Using
D20 Future rules I suppose, but I'm open to any better ideas (
Alternity?).
Some lesser ideas I'm tinkering with (not really original either):
Eberron by Night: Using the World of Darkness rules.
Warhammer 40,000 or RIFTS: Using Mutants & Masterminds rules.
The next story arc of my homebrew campaign world. Using D&D 4th Edition rules.
Gamma World! Stealing heavily from the Teenage Mutant Ninja Turtles Roleplaying Game but not using Palladium rules.