Random Adventure Generator

ThemeRevenge
In this adventure, some villain has so offended one or more of the characters that he cannot be suffered to live. (Alternatively, the injured party could hire the characters to avenge his honor.) The villain must be found or otherwise gotten at, setting up the final duel or showdown between villain and characters.
GoalEncounter Old Villain
If your campaign has a villain who shows up again and again to bedevil the heroes, then this is an episode featuring that villain. You might wish to roll once again on this section to see what the villain's goal is.
Story HookHero Offended
Someone greatly offends the hero, so much so that he'll pursue his offender right into the adventure. (Note that this usually means that the offender is a minion of the Master Villain. You'll have to decide whether the minion offended the hero precisely to bring him into the adventure or just as a side-effect of his ordinary villain activities.)
PlotA-B-C Quest
This is an epic sort of plot. In it, the heros are given (or undertake) a task to perform: The taking of a city, the rescue of an innocent, the destruction of a monster, the creation of a magical item, the defeat of a Master Villain, etc. But the path to victory is not a simple one. To get to their goal, Event A, they find that they must first accomplish some other task -- Event B. But when they undertake the task of accomplishing Event B, they find that they must first accomplish Event C. This goes on for several encounters, until the heroes accomplish all the obstacle events which prevent them from returning to Event A, their original goal.
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 SettingExotic Distant Land
The adventure will take the heroes to some fascinating and exotic distant country, where they'll have to cope with new customs, monsters unfamiliar to them, and very colorful NPC encounters; choose one of the more fascinating foreign lands from your campaign world.
Specific Setting ITavern/Inn
This is a classic fantasy setting, the residence of travelling heroes and the home of the tavern brawl.
Specific Setting IICatacombs
These can be catacombs beneath a living city or a ruined one; they can be long-forgotten or still in use.
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 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/NeutralHero Worshipper
Some youth -- an urchin, a brother or sister of one of the heroes, or a child run away from home -- hooks up with the heroes, following them wherever they go, being admiring, talking to everyone (neutrals and villains included) about how wonderful and powerful the heroes are.
Monster EncounterReconaissance Monster
At some point in the adventure, the Master Villain will become aware of the heroes' activities against him. If he has magical abilities or a magical servant, he will send some sort of quiet, clever monster to spy on the heroes. The heroes should have an opportunity to realize they're being spied upon, leading them to a mad scrable as they try to capture or destroy the spy.
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.
DeathtrapColiseum
If it's appropriate, you can have the heroes captured by the local authorities -- particularly when they're in an exotic land, lost world, or whatever -- and have them armed with gladiatorial gear and dropped into a coliseum for the entertainment of the locals. (Note that this works much better with fighting-type heroes than spellcasters.)
ChaseWater
Don't forget the water chase: Whether it's a battle of seamanship between naval vessels, a chase of rafts toward the inevitable waterfall ahead, a contest of canoeing ability, or a chase between the villain and his giant shark vs. the heroes and their dolphin friends, the water chase can be a distinctive and dramatic one.
Omen/ProphesyFortune Teller Predicts Doom
This is an ominous encounter: A fortune-teller predicts doom for one of the heroes, or for some community menaced by the Master Villain. Shortly after, some calamity should befall the hero: He can be attacked by an assassin, be in a building when it is struck by fire or an earthquake, or suffer other danger. Investigation of the events can then point the heroes toward the Master Villain as the event's instigator.
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 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 QuandryFriend Quandry
At a critical point in the story, one of the campaign's NPCs makes an impossible demand of one of the heroes.
Red HerringFalse Path to the Artifact
Once again, if the heroes have had too easy a time finding the artifact capable of destroying the villain, give them trouble this way: When they get to the place where the artifact is supposed to be contained, they find the coffer or chamber or whatever empty, obviously looted by robbers, who have scrawled such remarks as "Kelrog was here!" upon the walls.
Cruel TrickWanted by the Law
One final complication, one which occurs pretty frequently, is when the heroes are wanted by the law. When they're wanted by the law, they have to travel in secret and very limited in the resources they can acquire.

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