Random Adventure Generator

ThemeRomance
This sort of adventure (rarely played, but worthwhile anyway) has as its central plot the romance between two characters, usually a player-character and an NPC.
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.
PlotEvent
For this plot, choose some sort of event -- a tournament, a holiday, a celebration called by the king, a masked ball, or whatever -- and set the commencement of the Master Villain's plan against that backdrop.
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 ILegendary Forest
This classic adventure site is the sometimes dark and fearsom, sometimes light and cheerful, always magical and incomprehensible forest inhabited by the oldest elven trives and most terrifying monsters.
Specific Setting IIMansion of a Lord
This can be the home of a villain -- the characters may have to break in and rescue someone or steal evidence, or break out if they've been captured -- or of a heroic ally, in which case it may be used as the headquarters for the heroes' plans and activities.
Master VillainDestroyer
This villain is like the Corruptor, except that he likes destroying instead of corrupting. He operates like the Conqueror, moving in his armies -- often nonhuman or monstrous armies -- and destroying everything in sight. Again, the Destroyer could easily be an evil god or demon, meaning the heroes wil have to find his weakness in order to thwart his current plan.
Minor Villain IMistress 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.
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/NeutralIngenue in Distress
The heroes must protect some defenseless young innocent who is in danger from the villains. This person, perhaps the sheltered son or daughter of a nobleman or merchant, has no abilities at all but is sweet, charming, and in great need of help.
Monster EncounterNoble Beast
With this encounter, the heroes find that they have to capture -- but not injure -- some sort of powerful, noble beast in order to accomplish their mission. For instance, to reach a mountain-top aerie, they must capture pegasi and ride them up to their enemy.
Character EncounterPress Gang
In any port city, the heroes, in a tavern or hostel, may find themselves set upon by ruffians employed by the city; these ruffians use clubs and strike to subdue. If the heroes fight and beat the ruffians, they find themselves wanted by the law for assaulting officers of the peace. And if they fight and lose, they wake up to find themselves sailors, headed far away from their quest! Now they must decide whether they're going to jump ship, mutiny, or just settle down toa few years of seafaring life.
DeathtrapRock and a Hard Place
This trap starts out as an Animal Pit, Pit and the Pendulum, or Tomb Deathtrap, but an obvious escape suggests itself very early on. Trouble is, it leads into even worse danger. The hole out of the animal pit may lead to the lair of an even worse animal; it may lead through a succession of dangers (collapsing old catacombs, into an underground river, into a den of zombies) before the heroes reach the light.
ChaseEndurance
The Endurance Chase is not some sort of climactic chase -- it's a rugged, tiring, persistent pursuit that tests the characters to their limits. In this chase, the heroes and villains are pursuing one another across a lot of territory and they're not catching up with one another very fast. This may be a horseback pursuit across a hundred miles of savannah, a camel chase across several days' worth of desert, or a chase across arctic tundra.
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 WeaknessSecret Embarrassment
Finally, the villain may have some aberration or secret shame that will force him to flee when he is confronted with it. It could be something as simple as the fact that his nose is too big, or that he is a small and nebbishly wizard pretending to be some vast, powerful demonic power. When his shame is revealed, he is too humiliated to continue; this is a good option for comedy adventures.
Special ConditionNo Weapons Allowed
At some point in the story, the heroes must surrender their weapons. Perhaps they're visiting some quarter of the city where weapons are not allowed; or a particularly peace-loving temple. In any case, once they're there, they are attacked by enemies belonging to the Master Villain.
Moral QuandryAlly Quandry
You set up the situation so that the heroes have a good chance at defeating the Master Villain if they get the aid of two specific individuals, probably experts in fields relating to the villains' activities. But the two experts hate one another and refuse to work together, even if it costs them their world.
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 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.