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.
GoalRetrieve Item
This goal is like the Rescue, except the victim is an inanimate object. This item may be an artifact, a paper containing evidence against a character or patron, an antidote needed to save another NPC or palyer character, or just some item of sentimental value -- an item which one NPC hires the characters to steal from another NPC.
Story HookLegend and Rumor
In this classic story hook, the hero stumbles across some new or long-forgotten knowledge that promises great treasure or gain.
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 IDemi-human Community
In wilderness areas, this will be a large community of demi-humans -- elves, dwarves, halflings, whatever -- or intelligent nonhumans such as orcs. If your action is taking place in a city, this could be a hidden community (such as a secret underground dwarf community) or a section of the city inhabited mostly by demi-humans.
Specific Setting IICaves of Magical Folk
These can be either beautiful, glittering homes of gorgeous magical peoples, or the dank and terrifying lairs of horrible monsters.
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 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 IISingle-Minded Soldier
This most trustworthy of villain minions is the experienced, competent, persistent soldier -- a field-trained officer who serves the villain with military precision. He is usually encountered in the field as leader of the villain's field operations. He is not encountered directly until the middle of or the latter part of the adventure; until then, the heroes encounter only his subordinates.
Ally/NeutralCongenial Madman
This fellow is a pleasant, happy lunatic whom the heroes encounter; after the initial encounter, he follows them wherever they go, commenting on their plans, behaving strangely, getting underfoot, and -- very occassionally -- proving to be a real help.
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 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.
DeathtrapTomb Deathtraps
Another classic type of trap is the sort of triggered trap left behind in abandoned tombs, ruins, and catacombs. Here, a hero who touches the wrong step, floor tile, wall brick, torch bracket, mounted gemstone, or other device will trigger some sort of ancient trap designed to kill tomb-robbers and intruders.
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/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 WeaknessLove
The Master Villain possesses the "weakness" of genuine affection or love -- probably for some NPC, though it could be very intriguing if the object of his affections is a player-character. The heroes can then defeat the villain by holding his loved one hostage, or proving that his loved one will be seriously harmed, betrayed, or killed if the villain keeps up with his activity.
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 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.