Diana: Warrior Princess is an indie role-playing game written by Marcus Rowland and initially published by Heliograph Incorporated, based on an article describing the setting which originally appeared in Valkyrie magazine. It is distributed as a PDF via Steve Jackson Games. It describes a fictionalised version of the twentieth century as it might be seen a few thousand years from now.
The game is a parody of Xena: Warrior Princess, and its setting tries to portray the present day with the same level of accuracy that Xena portrays Ancient Greece - i.e. not much. Historical figures are distorted and confused with each other. Diana, Princess of Wales rides around in shining white motorcycle leathers on a semi-sentient motorbike, doing battle with the war-god, Landmines, and Bonnie Prince Charlie, from whom she took her mystic powers of Royalty. She is aided by Fergie, the Barbarian Red Ken and Wild Bill Gates, while Tony the Vampire Slayer battles the sorceress Thatcher and her masked assassin Archer. The milieu also includes figures such as Emperor Norton, Queen Victoria and the "disease" lepus (described as a scriptwriting error since lepus is actually a reference to rabbits).
Source: Wikipedia, "Diana:_Warrior_Princess," available under the CC-BY-SA License.