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.
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 HookOld Enemy
This is a straightforward story hook; the hero learns that his oldest enemy is back and is very active in the campaign, up to something. The hero will naturally want to investigate and will walk right into the story.
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.
ClimaxBloody Battle
This is the best Climax for an adventure involving the clash of mighty armies -- or for any adventure where, toward the end, the Master Villain and a large body of minions confront the heroes and their own troops. This finale is characterized by a monstrous clash between the two forces, with the heroes chewing through the enemy ranks to get at the Master Villain and his elite guards. It's strenuous, exciting, and classically simple.
General SettingOn the Sea
Most of the action occurs on the sea -- the heroes are shipborne for some reason, docking in lots of ports. Again, this is good for adventures where the heroes are investigating clues left all over the map, are part of some trading enterprise, or are being pursued by villains.
Specific Setting IMansion 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.
Specific Setting IIRuins
These can be the ruins of some ancient civilization, an abandoned temple or castle, incomprehensible blocks of stone arranged by ancient gods, etc. They can be magical or normal, inhabited by normal animals or by monsters, centers of magic or just tumbled-down buildings.
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 IHard-Eyed Advisor
This is the sort of villain whom the heroes see in the Master Villain's throne room. He's hard-eyed and scary; life means nothing to him and he enjoys killing. He's also a good advisor to his master.
Minor Villain IIMisguided Moralist
This fellow has been convinced that only by helping the villain achieve the Master Plan can he improve the world. He tends to be encountered all through the adventure's plot, usually escaping from the heroes and taunting them for their wrong thinking. Fortunately, he's no more effective as a villain than he is as a thinker.
Ally/NeutralGrumpy Old Professional
Again, the heroes need an expert in a certain field -- this time a craft or art, such as blacksmithing, engineering, horse-training, or whatever. The only or best professional they can find is an aged expert. He's grumpy, cranky, and sharp-tongued; he constantly complains about the food, the weather, his companions, the decline in skill of his co-workers since he was a young man, the road conditions, the rotten pay he's receiving, and so on.
Monster EncounterRavager
This is another classic monster encounter; the monster which is bedeviling a community or local area and will continue to do so unless the heroes destroy or defeat it. Yes, this is similar to the Master Villain of the same name, but the Ravager usually has no master plan -- it just wants to kill, destroy, or eat.
Character EncounterBelligerent Soldier
The billigerent one has just had his ears pinned back by his commanding officer and is anxious to take it out on some hapless civilian. If this is a city gate, he claims that the hero's papers are wrong or that he recognizes the hero from descriptions of a wanted criminal; if this is the streets, he insults the hero's lack of military bearing, pretty looks, clothes, smell, companion, or whatever it takes to provoke a reaction.
DeathtrapAnimal Pit
This is a classic trap of the adventure genre: The heroes (perhaps just one hero) are dropped into a pit filled with dangerous animals -- snakes, lions, bears, whatever. They must either fight the beasts or delay them until they can escape -- climb back out, open a secret door, break down a wall, have a rope lowered by friends above, etc.
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 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 ConditionMagic Doesn't Work Right
If the adventure is taking place on an alternate plane, then that plane's magic works oddly or not at all. (A spellcaster will find that just making himself useful is a challenge when none of his spells works.)
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 TrickVillain is Related to Hero
In this very irritating complication, one of the heroes discovers that the Master Villain is related to him. The villain might be his long-lost father or twin; perhaps this relative is not long-lost after all, but has secretly been a Master Villain for years, and only now has the hero discovered it.

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