My players stumble upon an abandoned version of one of my Dwarf Fortress cities.

I already know the whole layout backwards and forwards without needing to work with a map, and it has traps, epic architecture, purpose to every room, little random stuff scattered through, and I can usually come up with some kind of theme or ending to the dungeon for if they get that far into it. Easy peasy.

My favorite go to, one I've used twice in the same campaign and no one was the wiser, is to throw some ridiculous fight at the party out of nowhere, let them sweat it out for a round or two, and start dropping hints it isn't what it seems.

I had them stumble across a black dragon in a cave as a lvl 1 party once. After scaring the shit out of them, for a round or two, someone "finally noticed" that the wings seemed to be made of tar covered cloth. Druid did a nature check and realized that's not what a black dragon roar sounds like at all. Literally 5 kobolds in a dragon coat.

One time, I thought we had canceled but everyone pinged me about why I wasn't logged in to roll20 yet (got my weeks mixed up). Luckily one other person did too, so I told the party I was going to puppet their character so they would level up too. I had that character betray the party by leading them to a trap. They defeated the player character (I used their actual character sheet to fight the party), for them to discover it was a doppelganger, and the trap was the diopleganger's lair. they solved through a bunch of traps and random creatures from the diopleganger's managerie of tortured -to-the-point-of-insanity minor monsters until they found the actual player character that (as they discovered) had been kidnapped the night before.

One other time l, over lockdowns, I had a friend miss a few months of sessions due to some serious and very depressing circumstances. He still wanted to continue once life had calmed down. We were doing an Avernus campaign, and I had been NPCing his character, but I told him to fast forward to his character to the current party level (about 6 levels) and not tell anyone he was going to rejoin the play sessions or log into roll20 until I gave him the go ahead. About 15 minutes in, the party is sailing down the river Styx when they see a damaged flying fortress crash landing, streaking by overhead. They hear a hellish scream and see a buck naked tiefling jumping out of the ship directly for their raft. At this point my friend logs into discord and yells "I WANT MY SHIT BACK YOU IMPOSTER BASTARD!". combat began immediately whereupon he fought himself and regained all the loot the imposter had been carrying. The party had a hell of a good time that night, and he never did explain (in character) what hell actually happened to him.

A shopping trip can kill half a session if it's been a while. Then maybe one of the shopkeepers has a problem that would be worth one of the nicer items in their shop if it were taken care of for them.

Assuming a D&D 5e game, I load Kobold Fight Club and click until I find monsters I can build a little story around.

A while back (including enemies from Tome of Beasts) I got Spawn of Akyishigal and Giant Ants, and after a few overland battles they found a beleaguered anthill.

By the next session I had my dungeon made and some lore surrounding it.

The giant anthill had carved its way into an ancient tomb of an orcish warlord who had managed to seal the Demon Lord of Cockroaches with her in an attempt at everlasting life. The actions the players take can result in her rising as a Mummy Lord or in Akyishigal being freed.

All from going "Hey, these enemies work well together."

Here's a link to it:

The Mirrored Tomb of Yeskarra

If I have absolutely nothing prepared, like I don't even know anything about the world or the situation the players are in, then I reschedule session 1 ;)

You almost never have nothing prepared. If I didn't prepare for a session, it just means whatever was there gets built upon in a more rudimentary way, areas have less detail, characters are more rough, no nice maps, but otherwise everything is exactly the same. The stuff you do in preparation just means that the session will be better. If you don't prepare, you'll essentially just do "preparation" on the fly and it's called improvisation. You don't do drafts and discard them for something better, you just always go for the first thing that comes to mind.

So idk, for me, not preparing for a session is pretty simple, I just do everything the same just in less time.

Get yourself Sly Flourish’s Lazy Dungeonmaster and The Return of the Lazy Dungeonmaster, first of all.

To answer the question, think of a strong start, maybe a combat to give me room to think between turns. Think of 10 secrets and clues. Grab a map from Dyson. 5 Room Dungeon it. And if you’re pressed for time, ChatGpT can be super handy pulling together tables and last minute prep.

So, like usual then?

If it's a new game, I start off with a basic adventure I always have tucked away. A good starter adventure is a lifesaver sometimes.

If it's an ongoing game, then we probably have stuff we were still doing? Just recycle the prep from last time wherever possible and play for time. "Oh, yes, you have the treasure from the depths of the dungeon, but now your rivals have seized the place and you need to fight your way back out! Totally not just doing this to reuse the dungeon map."

If it's an ongoing game and we just had a good cutoff point? Thank god that player just arrived. Ask them what they're expecting will happen this session, nod sagely at their guesses and work from that. "Oh, you're hoping you'll fight that cult sometime soon? You never know, it might come up sooner than you think!"

Everything else is just good prep advice. Keep generic NPC templates and tokens you can use for anything. Use a whiteboard for any maps you need. Give your players control of the plot so you don't have to come up with it.

If I'm truly unprepared I'll just recommend we play a board game instead. With that said, if we are playing in a larger campaign I've often prepared lots of things that haven't been used with because they seemed like a likely path at some point that went untaken, and I might just nudge players in one of those directions and balance any numbers on the fly if it was prepped a couple levels before.

I don't schedule a game if I'm not going to be prepared

So, here is my approach, in the context of a campaign. On my campaign, I tend to have a short list of NPC/Faction/Place and enjoy keeping the campaign on a shorter space rather than a whole multiverse.

So my technique would involve.

• Ask the players to give me a summary of latest session, that I'll crosscheck with my notes.

• Ask the player what they want to do, following these events. having reccuring NPC/Places/factions mean that I can improvise how these person react to the event (if they do). This will easily burn a hour.

• While all of that happen, I have time to think about how to relaunch the story, either there is an event which absolutely makes sense in the context The local mafia isn't happy that you dismounted their drug production lab, when you come home you find a miniature coffin with a bullet inside in front of your door or, even though it's a bad practice, I throw a "randomish encounter" A big etheral cloud forms over the magic equipement store, and you can see some ethereal creature leaving that cloud and ear screams of bypasser being attacked The latter adds a combat buying me an extra hour to find-out why this shop exploded.

• Then, I can let the player investigate these events, it may-not be the most complicated investigation I ran, and kinda linear, However, it's enough to keep going to the end of the session, and have new elements to develop for next time

For a one shot ?

In general, I organize them when they're ready, and I have a lot of one-shot scenario ready on my computer, alternative would be pulling a zero prep game.

The Gamemaster's Apprentice is the single tool you need for this scenario. Add in a playing card oracle and you can basically randomly generate a session on the fly.

Play Battlestaions This was my last group’s actual fallback… that started to become our main game because it was more interesting than my campaign O.o

Is that honestly such a big deal? If it's long term chronicle/campaign than i'm sure you have lots of plot threads hanging around waiting to be woven into a new story. If it's a new chronicle just make a session zero - players will keep talking a make most work for you. And if it's a one-shot.. Well, than you improvise, i guess.

I gave myself a vague outline of a plan, I'll wing it.

First, vibe check. Let the players shoot the shit a little more than usual out of game. While they do this, you do a little last minute brainstorming or note-taking/reworking.

Second, if you let them drive the convo, they will usually give you some clues when they finally get bored and start asking each other to calm down and start the game. Things like "I want to find out what so and so has to say about the mission we just got from who's his face!" Or "I want to kick that (minion of the bbeg)'s ass! Let's get moving!"

This tells you what your players want. Now you have some focus on what you need to spitball.

Now it's down to your improv skills. Yes-and helps a ton here. You ask what they do and it just works, or works with consequences. Ask them to roll some checks and if they roll high and it isn't stupid they succed and do the thing or get the info.

If they roll low something bad but not lethal happens. Minions show up, NPCs laugh at them, etc etc.

If you panic, ask them to roll a check and figure out what is is for while they are rolling the die and adding the result. At some point it's just art which you get good at with practice.

Good luck!

Grab any two factions with competing interests, loosely define some scenario where they're narrowly deadlocked, hook the group in via a scheming interloper who has mysterious (TBD) motives. Hash out all details by yes-anding. If ever there's a lull, or I need a climax, the current underdog makes an unexpected power play.

It helps I'm playing Fate, so it doesn't require a lot of prep. My 2nd favorite system, CofD, also doesn't require a lot of prep. Dnd's math is so wonky it needs more prep.

In both of those systems stats are pretty constrained. A dude has like 5 health levels on average and you don't need to scale things to player level like that.

I usually have a couple factions in the game that are up to no good. They can always start some shit by kidnapping NPCs or advancing their plots. Maybe today's the day they dig too deep and a balrog awakens in Central Park.

If I have nothing prepped, it's goofy random sidequest night.

One of my favourite sessions ever started when the player the session was focused on called out due to work. With my plans derailed I had ninjas crash through the window, steal her famous recipe book, then run off and leap into the back of a van with her biggest rival at the wheel. It turned into a driving battle on the highway with characters leaping from vehicle to vehicle while a supervillain chef pelted them with capsaicin-laced muffins. It ended with an elderly PC duking it out with a morbidly obese NPC (neither of which had any points in fighting) in front of a police station. They traded single points of damage until the cops finished laughing and arrested them both.

I recommend you give the players a Bag of Beans. Its a chaos machine and a great method to get your players to do something fun without completely derailing the campaign. We all really enjoy the pink toads (random monsters) since you can just roll up something crazy and do a combat.

We had the mummy lord come up which ended up being a huge plot point after they let it sit for a while. It changed the course of what we wanted to play in a fun way.

This mostly happens to me when it is very clear that the session is going to be about resolving something about player X's backstory, and their work schedule changes.

The easiest way, is to use a generator, like https://donjon.bin.sh/scifi/random/.

I might not fully use the suggestion of "A minor executive named Jasper Catlow needs a crew to frame a rival named Porter Gammon for corporate espionage. However, the client hires a team of assassins to eliminate them after the job.", but it's easy enough to change some nouns to make an interesting one-shot.

Sexy goblin

Npc with a sob story, but they're shy so it takes some conversation (time to think and roll with what the players think might be going on) before they will reveal it.

I think one way I have seen was to at first session get list of few details about PCs, then pull out an adventure based on it. Eg. If your cleric told you there is a food his religion forbids, he is suddenly ordered to deal with a heretic who argues othertwise.

Wait for everyone to arrive. Even the late ones. Then order pizza. Fuck around until pizza arrives. Then everybody has to stop whatever they're doing to eat the pizza. By now it's 2 hours after starting time. Have NPCs socialize with the party. Throw a pack of goblins or something at them. Have the party go fight with the locals over how much of a reward they should get. The store is closing in 10 minutes so we have to pack up for the night. The end.