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.
GoalClear Name
The name of one of the characters or an NPC has been sullied and the characters must clear it. The characters must find out a) why the name has been smeared, b) who is responsible, and c) why the responsible party is doing it; then they must find evidence to convince everyone they're telling the truth.
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 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 ITemple/Church
This can be either the church of some lofty and good diety, or the dark and grisly temple of some horrid deity (doubtless filled with evil soldiers and monsters), or even the temple that the madman villain has dedicated to himself for when he becomes a god.
Specific Setting IITemple/Church
This can be either the church of some lofty and good diety, or the dark and grisly temple of some horrid deity (doubtless filled with evil soldiers and monsters), or even the temple that the madman villain has dedicated to himself for when he becomes a god.
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 ILovable Rogue
This character is like the Master Villain of the same name, except that he has no minions of his own and serves at someone else's bidding. However, he's very independent, not always working in his employer's best interests; he often makes fun of the Master Villain's pretensions and may suffer that villain's retaliation because of it.
Minor Villain IIMoronic Muscleman
This fellow is a huge, powerful monster of a fighter. His job is to smash anything the villain tells him to smash. He does that very well, but don't ask him to do any thinking; he has no time for such brainy stuff.
Ally/NeutralMerry Minstrel
This character follows the heroes in order that he might find inspiration for his song and storytelling. He can't be shut up; he sings all the day long and into the night, is a showoff before crowds, and is far too noisy for a party trying to remain unobserved.
Monster EncounterKing Beast
At some point in their adventure, the heroes run across a King Beast -- some enormous, intelligent monster (which speaks the Common tongue) which is the leader of its species. Perhaps it needs help; if the heroes help it they'll earn themselves a favor which the King Beast will repay at some later time in the adventure. Perhaps the heroes are in deadly danger and need help; the King Beast can be persuaded to help, but only in return for a deed or favor in the future.
Character EncounterBandit Gang
When the heroes are en route from one place to another, have them run across one of the local bandit gangs. The bandits are faster and far more numerous than the heroes. But the bandits stay back. Basically, they're bandits who admire courage and prowess, and the bandit leader will challenge one or all of the heroes to a test of bravery or ability -- such as a horserace, a duel, a wrestling match, a joust, an arm-wrestling match where scorpions sting the loser, etc.
DeathtrapFramed
One or more of the heroes is accused and convicted of a capital crime -- one for which the mandatory punishment is death. The heroes must escape or die, and they're escaping from the well-built, well-protected prison of the local authorities.
ChaseHorseback
This is a relatively short chase -- it only needs to go on for a mile or so before even the best horses are winded. If it goes on longer than that, the horses may collapse and perhaps die.
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 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 ConditionTime Limit
Finally, the most obvious condition to place on an adventure is to give it a time limit. If the Master Villain is going to conclude his evil spell in only three days, and his citadel is three hard days' riding away, then the heroes are going to be on the go all throughout the adventure -- with little time to rest, plan, gather allies, or anything except get to where they're going.
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 TrickHeroes Must Work with Villain
If they have to work for the villain, it's due to some hold he has over them -- probably, he's kidnapped one of their NPCs and will kill this person if his demands aren't met. Put the heroes through the encounter where they have to do something they are loathe to do, such as sack and pillage a temple, before they have the opportunity to retrieve their friend.

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