Here's an Idea: What if the Dungeon was Your House?
I think stories are most powerful when they are putting things together to create new things. The best stories are narrative Large Hadron Colliders, picking up elements from other stories, science, mythology, religion, and everywhere else and smashing them until they form new elements of awesomeness. Star Wars is about a monk with a sword made out of lasers fighting an evil samurai in space. The Dresden Files is about what if Merlin and Philip Marlowe went up against a series of Draculas, Tuatha de Danann, and Cthulhus, and also were the same person. Captain America: Civil War is a story about the time the Manchurian candidate fought John Galt, with help from his boyfriend, an army captain. All of the elements of all of these stories existed before the stories themselves did, but they had never been put together in exactly that way before. Roleplaying games can do the same thing. Here's an example of a way the roleplaying games can do that: what if the dungeon was your house?
Imagine this: you describe the characters (either newly created for this session or pre-existing characters in a fantasy-themed setting) encountering a huge dungeon. Maybe they find a map, maybe they're hired to explore it, maybe they just stumble upon it. Whatever. They initially fight some giant bugs in an entryway, which closes behind them with a cave-in. They're pretty much stuck in there unless they explore their way out. They say "We press on." You pick up their minis, and walk out of the room.
When your players finally follow you, they find that you've placed their minis in front of a ventilation grid in the other room (or a hole in the wall, or a small crack in the wainscotting, or whatever). You say, "You appear to have stumbled into a giant's home. Huge furniture towers above you. What do you do?"
From there, you can trigger random encounters - more giant bugs, giant rats, maybe even a giant dog (the size of a dragon!). Maybe there are allies in the form of other adventurers who got trapped in here without a way out - politics that they need to navigate. Maybe some of them have stopped believing in the rest of the world once their parents died, the last generation to live on the outside. Maybe there are semi-sentient rats they need to talk to. The whole point is, milk this for all it's worth, and don't skimp on the fights - a large part of the fun is going to be recontextualizing the space. Create situations where they need to set up ambushes. Maybe the elf needs to climb to the top of the bookshelf to fire arrows. Maybe they need to venture under the couch and fight dust bunnies. One inch equals five feet in the real world, so bring a measuring tape and move the characters that way. Spells, attacks, everything becomes different when the characters are tiny in a world that you're intimately familiar with.
Just to be clear, this post isn't necessarily general, or applicable to every table. I know that. This post is about a cool idea I had, that I wanted to make available to you. Also, I wanted to publish it on the internet so that when someone steals it, I can point to this post as prior art.
Oh, obviously, the finale of the dungeon is that you have to fight the giant that's sleeping in your bed. Come on.