I've run a lot of D&D campaigns, and about half of them were outside the box of standard fantasy dungeon crawls. Though the setting and genre might have changed, somehow the way I ran them always made them D&D, even if neither of the Ds were actually represented in the game.
I thought it might be a pleasant exercise to outline some of the more memorable campaigns just to horrify more conservative grognards. All of the games listed below used 2e, 3e, or my own perversion of the d20 rules.
The D&D Games
-A war between the elemental forces of fire and ice over an isolated, fantastic version of Iceland, as a foreign tree deity tries to get its foot in the door and chase all the wyrms off the island. This campaign boasted Grendel, the Dream of the Rood, a Bjork cognate, and the fatalistic dragon from John Gardner's Grendel.
-A miserable princess escapes a forced marriage, and embarks on a quest to kill the circle of traitorous knights that betrayed her father the king. High production values didn't help me with this one, it stank.
-The unjust tyrant is responsible for many injustices, including personally wronging each of the player characters. They embark upon a campaign of domestic terrorism, assassinations, and eventually, revolution. Their adventures are punctuated by frequent flashbacks to before they became obsessed with vengeance.
-A group of friends is raised amongst a community descended entirely from adventurers, but must leave their home when it (and many others' homes) are threatened by an expanding empire of psionic slavers. This campaign boasted two adventuring parties played by different players, operating contemporaneously in the same world. One was the party of exiles, and the other was charged with destabilizing the slavers' targets.
-The Sahara desert as never seen before, the strange people that live in it, and the even stranger deities. The culture was based on the fascinating Tuareg people, to whom much Frank Herbert's Fremen owe a large creative debt. Iron was considered magical, and the goat men were to be the primary nemesis, though this didn't quite take off.
-A fantasic retelling of the reconquista in which the players were the personal playthings of a decidedly malicious creator deity. Drew strongly on the early surrealist book "Les Chants de Maldoror" by the Comte de Lautreamont.
-A kingdom that spared itself annihilation by using magic to cut itself off from the outside world, yet remained in danger of destroying itself. This setting had everything, from the good prince player fighting the evil prince player for the crown, to the hex crawl, to the city-based adventure, to two competing parties of players questing for the same item --more about this later, it's probably worth writing about in more detail.
Next: The Weird Games.