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.
GoalWin War
In this adventure or set of adventures, the characters become part of an army -- a force assaulting another kingdom, perhaps, or an army defending one realm from another.
Story HookMystery Woman
Create an NPC "mystery woman" sure to be fascinating to your hero and have her keep appearing inexplicably in his life. As he becomes interested and investigates her, he keeps stumbling across the villain's plans and becomes inextricably mired in the plot. (For female player-characters, the Mystery Man is just as useful.)
PlotGeographic Progression
This is the simplest sort of adventure plot. The heroes have an area to investigate or travel through; they have encounters based on where they are. For instance, the traditional dungeon, where monsters are tied to specific rooms or areas. Or, if the heroes are travelling along a narrow valley or through an enchanted forest, they might suffer ambushes and other encounters fixed to various points along their travel plan. The plot, then, is getting to the villain by surviving the intervening obstacle encounters.
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 ICatacombs
These can be catacombs beneath a living city or a ruined one; they can be long-forgotten or still in use.
Specific Setting IIMilitary Encampment
This is best used in an episode involving warfare; it could be the good-guy army's encampment, from which the heroes launch their adventures, or the villains' encampment, in which case the heroes might have to sneak in on a mission or escape from it if they're captured.
Master VillainOrganizer
This Master Villain is the head of the local criminal syndicate -- the Thieve's Guild or slaver ring, for instance. He's cold-hearted and unsympathetic, and human life means nothing to him. He employs assassins and musclemen against the heroes, and can only be reasoned with when it's going to profit him more to cooperate with the heroes than kill them.
Minor Villain IInquisitor
This villain is the one who interrogates the heroes and NPCs captured by the villains. He accompanies the other Minor Villain out into the field and works on anyone captured; he enjoys inflicting pain and suffering.
Minor Villain IIInquisitor
This villain is the one who interrogates the heroes and NPCs captured by the villains. He accompanies the other Minor Villain out into the field and works on anyone captured; he enjoys inflicting pain and suffering.
Ally/NeutralRomantic Loony
Somewhere, the heroes bump into a lunatic who falls immediately in love with a player-character and won't leave him or her alone. This character may be a love-smitten village lass or nebbishy adventurer. Whatever the origin, this character must be hopelessly in love with the character but have some trait which keeps the character from reciprocating; perhaps the loony is too plain, too crazed, or too stupid. Whatever, he or she really is sincere in his affection for the character.
Monster EncounterTerrain Monster
Don't forget the simple run-in with the animal belonging to the terrain where the heroes are: Every type of wilderness has its predators and big, nasty herbivores.
Character EncounterLying Accuser
A captured thief may accuse the character of putting him up to the theft; an abandoned mother may accuse the hero of fathering the child; a reputable witness (working for the Master Villain) may accuse the hero of a murder or robbery. The hero shouldn't know what he's accused of until he's hauled in by the authorities.
DeathtrapDemolition Zone
In this classic deathtrap, the heroes are placed (usually bound and weaponless) in some building or area just as it's due to be destroyed.
ChaseFootrace
The chase involves the characters on foot, probably through such terrain as city streets or the corridors of a palace. One hero may realize that the's being pursued by a party of enemies and choose to run for it; the heroes may have caught up to the Master Villain, prompting him to run for his life.
Omen/ProphesyBirthmark
One of the heroes has a birthmark that pertains to the adventure in some way. He may have a birthmark identical to some NPC -- for instance, some person endangered by the Master Villain. This mystery can give the hero his reason to become involved. Alternatively, his birthmark may mark him as a hero fulfilling some ancient prophecy.
Secret WeaknessHoly Symbol
The villain may have the traditional weakness to a specific holy symbol -- but don't choose just an ordinary one. It may be a holly symbol no longer used by the church, or may be some forgotten variation of the current symbol. (For instance, the cross may not work, but a variation -- such as the Roman cross -- might; alternatively, it might have to be a holy symbol which has undergone some unfamiliar ritual.)
Special ConditionNo Lawbreaking
For some reason, at one point in the story, the heroes cannot allow themselves to break the law -- even when it would help them greatly to do so. For instance, the heroes may be asking for the help of a king whose word is law and whose power is immense. When they arrive for their audience, an emissary of the Master Villain is making a similar plea for help. If the heroes attack and kill that emissary, they will lose any chance at the king's help -- in fact, he may order their execution.
Moral QuandryHonor Quandry
You want to use this on the character with the most strongly developed sense of personal honor -- someone who has lived all his life by a strict code. Toward the end of the adventure, this character realizes that the best way to defeat the Master Villain is a violation of that code. For instance, the character might be a paladin, who discovers that the only possible way for the heroes to defeat the Master Villain is to sneak up on him and stab him in the back.
Red HerringExtraneous Details
When giving the heroes details on their enemy -- for instance, details they are learning from investigations and readings -- you can give them just a few details too many. This may prompt the heroes to investigate the "extra" (i.e., irrelevant) details in addition to the relevant onces, thus losing them valuable time.
Cruel TrickMission is a Ruse
In the course of their adventuring, the heroes discover they have been tricked into performing a mission which helps the Master Villain.

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