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.
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.
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.
ClimaxThrone Room Duel
This is set up much like the Scattered Duels, except that you don't separate the heroes. It's harder to control whom fights who in this situation... but if it doesn't matter who has the final duel with the Master Villain, this is a classic climax choice.
General SettingAlternate Plane
Most of the story takes place in an alternate dimension; this implies that either the PCs or the villains, or both, have magic powerful enough to bridge the dimensional barrier, or that the PCs stumble across some dimensional portal.
Specific Setting IPalace of the King
The heroes could be here for many, many different reasons: Trying to get a favor from the ruler, part of some nobleman's retinue, members of the palace guard, sneaking in to save the ruler from assassins, sneaking in to assassinate the ruler, thrown into the dungeon for crimes they did or didn't commit, etc.
Specific Setting IIMilitary Encampment
This is best used in an episode involving warfare; it could be the good-guy army's encampment, from which the heroes launch their adventures, or the villains' encampment, in which case the heroes might have to sneak in on a mission or escape from it if they're captured.
Master VillainConqueror
This character is moving his army in to take over; that's what he lives for. He's been the enemy of your characters' nation's ruler, and has launched a full-scale invasion of your characters' favorite nation. The heroes have to beat their way through or elude his hordes of soldiers in order to get at him; better yet, they might lead their own nation's troops against his and outthink him in military fashion.
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/NeutralGovernment Observer
For some reason, the heroes' ruler wants one of his own people accompanying them. Whatever the reason, the heroes are now stuck with a haughty, self-important royal observer, an expert in (probably) military tactics or espionage. He continually offers unwanted advice and tends to get the heroes into trouble by pulling rank whenever he's not satisfied.
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 EncounterNew Enemy
In the course of his ordinary activies, one of the heroes can make a New Enemy. Hurrying along the street, he can bump into a disagreeable fighter for whom an apology isn't enough; in a tavern, he can make some innocuous remark that you deliberately have the irritable fellow misconstrue as an insult. The New Enemy will only exchange heated words with the hero at this point, but will appear again later in the adventure and will eventually have to fight the hero.
DeathtrapAvalanche
This is an outdoors trap. Some time when the heroes are in a narrow canyon or gorge, or are on a snow-covered mountain, their enemies can arrange to dump an avalanche upon them (rocks and boulders in the first instance, snow in the second).
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/ProphesyInnocent Fulfills Prophecy
An innocent could fulfill a prophecy -- one which endangers his/her life. This innocent might, for instance, be the one who is supposed to slay the king, but is not a mighty adventurer able to protect himself from the king; the heroes may find themselves sheltering and helping this poor dupe.
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 ConditionNo Hurting the Villain
For some reason, the heroes cannot afford to fight the villain directly. For instance, what if a demon possesses the body of the child of one of the characters, or a very important child spoken of in prophecy, one without whom the world will perish?
Moral QuandryRespect Quandry
This is much like the Ally Quandry, only at a greater distance. The heroes have been utilizing the aid of two (or more) powerful NPC allies. Now, in the course of the adventure, the heroes come across a task which can be accomplished in one of two ways -- say, through military intervention or by esoteric magic. The problem is, the NPC allies are arguing for different choices, and the one whom the heores choose against will no longer aid them.
Red HerringLying Rumor
This is the worst and most useful type of red herring -- the interesting rumor which just happens to be false. In adventures of this sort, the best Lying Rumor concerns the Master Villain; it gives the heroes some "important" information about him which later turns out to be useless.
Cruel TrickNPC Turns Traitor
He may alert he enemy when the heroes are planning a raid; he may steal the artifact and take it to the villain; he may stab a hero or important NPC in the back (literally) before departing.

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