Aight, so literature can provide us fantastic ideas for modules. I don't know why I never realized this.
About ten years ago, I tried to turn Bret Harte's short story "The Outcasts of Poker Flat" into a Deadlands adventure. It was a complete and utter failure. As soon as the folks of Poker Flat tried to run the PCs out of town, they wanted to start shooting. When I informed them that this would lead to their instant demise (five people vs. a town, even a small one, is a grim prospect) they went out into the wilderness....
........and immediately came to the conclusion that the townsfolk were under the spell of some kind of malignant entity, and that the preacher must be an evil servant of the Reckoners who needed to be killed. They immediately began planning to assassinate him...
....and then the party started bickering and it ended with them all splitting up and yeah. For a long time after that I was of the idea that stories were stories and games were games, and never the twain should meet.
Flash forward: I'm a high school English teacher and I'm into both classic literature and D&D. I download "A Thousand Dead Babies," and a few days after I finish reading it, I realize:
Dude, this is Nathaniel Hawthorne's "Young Goodman Brown" but in D&D world.
So then I start thinking about sandboxy stuff and non-sandboxy stuff I can steal from the literature I teach.
Beowulf- A wimpy-ass king needs YOU to get rid of a supposedly invincible monster. (Also, oddly, the premise of the old TSR module "Wizard's Challenge II..) He will drop serious treasure on you if you can solve his little problem.
-A wimpy-ass king's swank castle stands empty because some monster haunts it. Kill the monster, get a free castle.
-There's a horrible sea witch at the bottom of a haunted, glowing lake. Supposedly she is in possession of a magic sword crafted by giants in ages past. Just sayin'. You like magic swords, right?
-Your old-ass king needs YOU to save him from taking on a monster he can't dial in his decrepitude.
-The old king died fighting a dragon. They buried him in a tower full of jewels. Feeling lucky?
Hamlet- The castle is haunted. They say the ghost looks like the recently deceased king....
-Investigate the cause of the prince's recent madness.
-Escort the crazy-ass prince to the neighboring allied kingdom and give his secret death warrant to the king there.
-Help the prince sneak back into his homeland.
Macbeth- Some witches show up and tell the characters (or just one) they're destined for something great.
-Someone's done killed the King overnight. Who was it?
-An exiled Prince needs you to help kill the guy who jacked his dad's throne
-The King wants you to off this guy....and his son.
-The King wants you to off this traitor's entire family.
If you don't want your PCs running around with kings all the time, you can easily make them burgomeisters or guildmasters or high priests or mayors or well-to-do artisans or whatever.
Any of these could simply be rendered as rumors, too. The castle is supposedly haunted. The king is rumored to be concerned with the prince's madness, etc.
Campaign prep and lesson planning at the same time....? Madness.