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 HookDying Delivery
On some occassion when the hero is out wandering the streets or is otherwise all alone, a dying man bumbs into him, hands him something, says a few words, and dies.
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 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 IShacktown of the Oppressed
Part of the action centers around the tenements or shacks of the worst part of town; perhaps an allied NPC lives here or the characters are fugitives hiding out in the nasty part of town.
Specific Setting IIMadman'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.
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 IChief Assassin
The Chief Assassin is the favorite killer of the Master Villain. The Assassin works mostly in the field, first killing witnesses who might prove harmful to his master, then zeroing in on the player-characters. He usually meets his end before the adventure's climax, but he may taken one of the heroes down with him.
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/NeutralTalkative Barkeep
This classic encounter is the garrulous innkeeper who has information the characters want; trouble is, they'll have to bribe him to get it, or agree to stay at his inn, or buy a lavish meal, or listen to his incessant stories about his career in the army, or whatever.
Monster EncounterLoving Deceiver
One of the player-characters, specifically one of the better-looking ones, attracts the attentions of a very attractive local of the opposite sex. This local person, encountered in unthreatening surroundings, invites the hero off to a liason away from his friends and other people. Of course, this person is a human-appearing monster of some sort; once alone with the character, he/she will attack the character with monstrous intent.
Character EncounterOld Friend at the Wrong Time
When the heroes are trying to sneak through a guardpost, citadel, or city where they can't afford to be recognized, one of the characters' old friends recognizes him and loudly renews their acquaintance in full view of the guards looking for the characters. This usually leads to an exciting chase as the heroes must escape.
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.
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/ProphesyReincarnation
The hero, seeing the portrait of some long-dead nobleman, may be surprised to see his own face staring back at him. All evidence points to the fact that our hero is the reincarnation of this person, and the Master Villain may desire to destroy any trace of that nobleman's existence. Just as appropriately, this long-dead nobleman may have died after making some important choice -- such as choosing love over career or career over friends; and the choice he faced is identical to the one the hero now faces. Will our hero defy the prophecy and choose as he did in a previous life, or will he choose the other option and see what happens?
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 ConditionOmnipresent Observer
If a wizard, demigod or god has forced the heroes to undertake this quest, he may be with them continually -- in spirit. He can't help them, but does magically watch everything they do. And when they do something he doesn't like, he tells them about it -- loudly and nastily. (This is distressing when they're trying to break into a fortress or sneak through enemy lines.)
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 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.