You, a wizard, have a secret wizard base. Pesky adventurers and who knows what else would simply love to find it and loot all of your precious stuff. Here are some things to consider during construction.
In the desolate wastes of Antarctica, under thick layers of ice and snow, forgotten by the world and only remembered in a few databases of the ancients: There lies Psilabs; a major research complex into the human psyche and the powers of the human mind.
Stronghold made for the liche Haukagaron. He was betrayed at the last and Castle Kaukenn was pulled into the Abyssal realms.
An open room lay before them, occupied only by a few cobwebs and dust. Upon entering, a phrase is seen on one wall. One of them utters the phrase out of wonder for its meaning, unknowingly activating the room. An eye opens on the wall in front of the poor souls and with a quick flash of light, the last thing heard from the room is heart retching screams... then silence.
Lost to the mysts of time and catastrophe, the fabled Zhao Zwehian Library has reappeared. Or at least, part of it has...
"She sails up'n'down the Tristis River. All them river folk see her an' give her a wide berth. Superstitious lot, them river folk. 'Course, we adventurers kill of monstrous superstitions of the rich type on a daily basis! Who're we ta judge? So's anyways, she is said to only appear when the moon is full and the werewolves howl. And though she's ne'er violent, you can always 'ear a moanin' sound. I got no idea what's aboard that ship, but whate'er it is, I want nothin' to do with it."
-Old Gerald, man in the pub
"The Walk. Oh, aye, I've heard o' the walk. Its this peninsula, south of us, where the sides o' this peninsula are cliffs. At the end o' this peninsula is this big area, riddles with caves. In them caves is a huge treasure. At least, according to these rumors I've heard. 'Course, them caves have been taken over by orcs. I'd go take the treasure meself if I was younger."
-Old Gerald, man in the pub
Something is killing and eating the people of Th'gil. This monster displays cleverness, strength, and a thirst for blood. The PCs have stumbled into this town. Will they leave by walking or by dieing?
After waking up groggily in the middle of a floating wizard's tower, the players must find some way to escape before being slain by the beast that stalks them. Time is ticking and the cat is always watching . . .
A Five Room Dungeon about finding the Imperial city of The Lost Empire.
From that silent place fear flows in unseen waves, like white fog. The shadows are many, and the wind breathes cold through the broken battlements and casements. Through it's frowning walls and dark window openings there's a lantern of the spirit which none see by but those who bear it.
Welcome to Uhgramudd, you'll never find a more disgusting, remote, fly-ridden, swampy Hell than this. Get in, kill the Lizards, grab the loot, get out. Simple, right?
This is an introductory low-level adventure I use to get familiar with players I meet online, to see if our play styles clash in any way. So far, it has weeded out a few undesirables and scored a few keepers. I am quite satisfied with the layout and have run it multiple times, with slight variations for level/abilities of the player characters.
In local legend, the Halls are fairly old, with stories of people disappearing going back for hundreds of years, said to be taken by the Faeries. In actuality, the Halls are much older.
"What you wanna go messin' around up in the mountains for? Ain't nothin' up there but snow, and wolves, and more snow.
Yer lookin' for the old tomb? Take my advice, boys. Let that tomb alone. There ain't nothin up there you ought be messin' with. No money, no treasure, no fame, just ice. And death."
Remember Harold and his purple crayon?
"The wind-driven snow parts for the barest of seconds, revealing a glimpse of refuge from the deadly storm. It’s a massive sapphire pyramid. Yet you know of nothing like it in this area…"
Not named for an resident beast, but for the multitude of winding, mazelike passages fraught with danger.
The heroes storm the Temple of R’gu, the God From The Stars, to steal the Ruby of the Winged Master
The powerful wizard Sumuho styled himself as a god and was worshipped far and wide. After his fall, his vast temple sank into the desert long ago. What secrets lie in the Sanctuary of Sumuho?
Pick up a pathology/microbiology book, and add the diseases/syndroms to your game. Your players will freak out.
Coughed at? Diphteria. or tuberculosis?
Drunk from a muddy stream? Or just walked through? Well, let us introduce you to schistosomiasis...
Hit by a stream of energy? Too moch mana is ust like too much radioactivity - perhaps all mages could develop cancer early if too powerful...