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.
GoalProtect Endangered NPC(s)
One or more NPCs are in danger, and the characters must protect them. They might be doing this for a reward, or because one or more of the NPCs is a friend or relative of the character. You need to decide what the characters are protecting the NPCs from. The NPC might be a wealthy or powerful person being sought by assassins or kidnappers. The NPC might be a whole village of peasants who are being terrorized by a bandit chieftan.
Story HookLegend and Rumor
In this classic story hook, the hero stumbles across some new or long-forgotten knowledge that promises great treasure or gain.
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.
ClimaxPrevented Deed
Here, the heroes have been defeated -- captured by the Master Villain, or so thoroughly cut up by his minions that all believe them to be dead. And the heroes have learned, from the bragging of the villain, loose talk of his minions, or examination of clues, what is the crucial event of his master plan. In any case, the battered and bruised heroes must race to this site and have their final confrontation with the villain, bursting in on him and his minions just as the knife or final word or key is poised, and prevent the awful deed from taking place -- and, incidentally, defeat the master villain and minions who beat them previously.
General SettingCosmopolitan City
Most of the story takes place in a large, sophisticated city; center the villain's plot and activities around that city. This setting is best suited to adventures involving more people than monsters; most of your villains should be human or demi-human.
Specific Setting IMadman's Fortress
This is the citadel of a major enemy: Strong, unassailable, filled with soldiers and monsters, lined with secret passages and deathtraps; not a wholesome place for adventurers to spend their time.
Specific Setting IIDemi-human Community
In wilderness areas, this will be a large community of demi-humans -- elves, dwarves, halflings, whatever -- or intelligent nonhumans such as orcs. If your action is taking place in a city, this could be a hidden community (such as a secret underground dwarf community) or a section of the city inhabited mostly by demi-humans.
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 ISnivelling Vizier
The Vizier is a throne-room villain. Functionally, he's rather like the Hard-Eyed Advisor, offering tactics and advice to his master; but he's an ooily, sleazy, cowardly sycophant. He's usually brilliant in his field of advice but has no combat abilities.
Minor Villain IICoward
This character is an ordinary grunt minion of the Master Villain, but he's a coward. He's deathly afraid of the Villain and the heroes. He's best used when you plan to have the heroes captured; by his mannerisms, you can make it clear to them that this fellow is a coward and they will begin to work on him psychologically.
Ally/NeutralChildhood Friend with a Dark Secret
One of the heroes is accompanied by one of his childhood friends... but said friend now has a Dark Secret. He does strange and mysterious things (sneaks off to send messages, or behaves strangely around certain NPCs, or is scared to death of certain harmless animals or situations) and will not explain why to his PC friend until late in the story.
Monster EncounterAssassin Monster
This mosnter, at some time in the adventure, is sent by the Master Villain to attack one or more heroes when they're at their most vulnerable -- asleep, enjoying themselves, etc. Usually, the Assassin Monster attacks, but the hero, though injured, is able to hold it off long enough for his friends to respond to his shouts. The Assassin Monster is usually killed by his friends, who can then speculate on who sent it and why.
Character EncounterThief
At some point in their adventure, the heroes have a run-in with thieves.
DeathtrapPit and the Pendulum
Actually, we're applying this term to any of many time-delay deathtraps. In this sort of trap, the villains capture the heroes and place them in a trap which will soon kill them -- it operates on a delay, often based on a timing device or a burning fuse.
ChaseAerial
The heroes could be riding pegasi or friendly griffons or allied great eagles; the villains could be carried aloft by gargoyles or demons. The prospect of taking a mile-long fall if one's mount is hit is a very daunting and challenging one for the hero.
Omen/ProphesyComet's Progress
Events during the adventure may be enlivened by a large and menacing comet which appears in the night sky for several days during the scenario; the locals take it for an omen of doom. The comet may be the result of magic being used by the Master Villain, or the comet's appearance can pertain to an old legend involving the Master Villain.
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 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 HerringLoony who Has It Wrong
You can have the heroes "aided" by a so-called expert who is actually a lunatic who doesn't know anything about what he's talking about. Once he's led the heroes off to some remote part of the continent, his evasive answers and bizarre behaviour will alert them that he really doesn't know anything about what he's pretended to be an expert on.
Cruel TrickNPC Turns Traitor
He may alert he enemy when the heroes are planning a raid; he may steal the artifact and take it to the villain; he may stab a hero or important NPC in the back (literally) before departing.

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