Random Adventure Generator

ThemeAction/Adventure
This is the most common and straightforward sort of adventure there is. In the Action/Adventure scenario, you present your characters with a task and then confront them with obstacles to overcome in order to accomplish the task successfully.
GoalThwart Monstrous Plan
This is a classic fantasy-adventure plot: The characters learn of some horrible plan made by a monstrous enemy, and must thwart it before the kingdom is lost or the world is destroyed. This is an epic goal, and usually requires that the characters go to all sorts of places, rounding up allies and artifacts, before being strong enough to face their enemy.
Story HookMissing Memories
One or more of the PCs wakes up with no memory of the recent past, and now they find themselves in some kind of trouble they don't understand. The PCs must find the reason for the memory lapse, and solve any problems they uncover in the meantime.
PlotSeries of Villains
This is a very dramatic plot, and very well-suited to oriental campaigns. In it, the heroes have undertaken a quest, usually the finding and defeat of the Master Villain. They may have to travel to his citadel, or head off in another direction to find some artifact capable of defeating him, or run away from pursuing villains until they can figure out what's going on. All along their route, they are set upon by villains -- each villain has a name and distinct personality, and each encounter is life-or-death for the heroes and villains; the villain never escapes to safety if the tide turns against him, he fights unto death.
ClimaxChase to Ground
First, you have the Heroes Chasing the Villain. The villain, after a series of encounters with the heroes, is running to safety, to some place where he can acquire more power, or to somehwere he can accomplish some dread purpose such as assassination or mass murder. The heroes chase him, have to deal with the obstacles he leaves behind, and finally catch up to him before or just as he reaches his goal. Here, we have the final duel between the villains forces and the heroes. Second, you have the Villain Chasing the Heroes. Often, in a story like this, the heroes have found out how to defeat the villain -- such as getting to a particular temple and conducting a particular ritual. The villain chases them all through their quest, catching up to them just as they're commenciing their ritual; they must, with heroic effort, conclude the ritual while suffering his attacks. Third, you have the Master Villain's Sudden Escape Attempt. This takes place in adventures where the Master Villain's identity is unknown until the end. His identity is revealed and he makes a sudden bolt for freedom; the heroes give chase. This usually results in a dangerous foot-chase through nasty terrain -- such as across rooftops, through the dungeons, or across an active battlefield.
General SettingOn the Road
Most of the adventure takes place on the road, as the heroes are travelling from place to place. This is especially good for adventures where heroes are investigating a wide-ranging mystery, are part of a caravan, or are being pursued by loathesome villains.
Specific Setting IClassic Dungeon
This would be the standard monster-filled labyrinth; perhaps it's a nesting ground for the master villain's monster troops.
Specific Setting IILost City
This is the remnant of some lost civilization or expedition, still thriving in some forgotten corner of the world. Remnants of lost civilizations can even inhabit cavern systems beneath campaign cities, preying on the above-worlders for their goods, slaves, and sacrifices.
Master VillainZealot
This villain is like the Conqueror, but he's not trying to conquer to own; he's trying to purge the world of something he feels is pure evil (another religion, a human, demi-human, or nonhuman race of sentient beings, a custom). He operates just like the Conqueror, enslaving or killing all those who belong to the "wrong" race or philosophy.
Minor Villain ICorrupted Hero
This villain was once a hero, possibly one known to the players. He was seduced by the dark side of the dungeon master. Because of his own weakness, or of a curse, he has become a villain, a pawn of the Master Villain.
Minor Villain IIMistress with a Heart of Gold
This character is much like the "Lover or Daughter of Villain" type of Mystery Woman from the Story Hooks section. In this case, she usually accompanies the Master Villain, but sometimes goes on missions of her own, where she runs into and develops affection for one of the player-characters.
Ally/NeutralObsequious Merchant
This fellow is the owner of the caravan the heroes are protecting, or the merchant the heroes encounter when they desperately need to buy something. He is oily, ever-flattering, overly agreeable, and is a sharp bargainer; the heroes will not find him willing to give them a sale price.
Monster EncounterBeast Amok
Some time when the heroes are in a village or city, an animal, probably an otherwise tame or captured beast, is set loose by the villain's minions or driven mad by the Master Villain. The beast goes berserk in the crowds; if the heroes aren't inclined to capture or kill it, it goes after them.
Character EncounterMean Drunk
The Mean Drunk works much like the Belligerent Soldier except that he's not as tough, is of course drunk, and is usually accompanied by other Mean Drunks.
DeathtrapAnimal Pit
This is a classic trap of the adventure genre: The heroes (perhaps just one hero) are dropped into a pit filled with dangerous animals -- snakes, lions, bears, whatever. They must either fight the beasts or delay them until they can escape -- climb back out, open a secret door, break down a wall, have a rope lowered by friends above, etc.
ChaseSpecial Terrain
You can make any chase more memorable by having it take place in a setting to which it is utterly unsuited. For instance, horse chases are fine and dramatic when they take place through the forest, out in the open plains, or along a road -- but they become diabolical when they take place inside the Royal Palace or in dangerous, labrynthine, treacherous catacombs.
Omen/ProphesyHero Fulfills Prophecy
This is the most useful sort of prophecy. In the early part of the adventure, one of the heroes discovers that he fulfills some ancient prophecy.
Secret WeaknessLack of Familiarity
The Master Villain, if he comes from the past or another dimension, or belongs to an alien race, might be sufficiently unfamiliar with this world that he essentially defeats himself. How? By making incorrect guesses about human behaviour. One classic error involves underestimating the human capacity for self-sacrifice.
Special ConditionCoping with a Curse
The curse might be making the hero progressively uglier, might be draining out his life-force (he's losing experience which will be retruned if he succeeds), or might be making him progressively insane. Each day, as he sees his reflection in a mirror or pond or fountain, he'll know himself to be less than he used to be.
Moral QuandrySaving Quandry
Finally, another classic quandry puts the heroes in the position of choosing between a grand opportunity to hurt the Master Villain -- or saving the lives of a number of individuals.
Red HerringArtifact that Doesn't Work
Often, epic quests against powerful Master Villains require that the heroes find some legendary artifact, the only object which can defeat the villain. If your heroes have had no trouble getting to the artifact -- they've effortlessly sliced through every obstacle you've put in their path and are confidently advancing on the resting place of the magical item -- you can have it not work.
Cruel TrickVillain is Related to Hero
In this very irritating complication, one of the heroes discovers that the Master Villain is related to him. The villain might be his long-lost father or twin; perhaps this relative is not long-lost after all, but has secretly been a Master Villain for years, and only now has the hero discovered it.

Based upon tables from the Dungeon Master's Design Kit by TSR, Inc.