Some friends drop in looking for an impromptu game. Or maybe they decide to turn left and explore the shaft that leads to a blank spot on your graph paper. Or perhaps the game moved to another location and your prep work was left behind.

A disaster in the making? No, an opportunity.

A good five-encounter dungeon can easily serve as an evening’s entertainment. So even if your prep time is just the 30 minutes the players are using to get their character sheets together, here’s a quick 5-room dungeon you can throw together that’s guaranteed to save the night.

1. “We got trouble!”

A great way to get the dice rolling — run into a band of bad guys right off. So fill the hall with mooks. From goblins to gnolls, from kobolds to orcs, just drop an overwhelming number of some monstrous humanoids on the PCs. The more, they merrier. Just make sure they are one-hit wonders relative to any warrior-type PCs in your group. One hit from most weapons should take them down. Throw in a couple of bigger and tougher versions, if you wish, but the key thing is to have a mass combat where everyone has to throw in and get bloody.

And the treasure? Well, even goblins always carry a couple of coppers in their pockets, I suppose.

2. “It’s Alive!” 

We must have something for the clerics to do. The answer: Undead. Yes, we love our skeletons that clatter, our zombies that shuffle, and those ghouls that chill you to the bone. Find an undead at the appropriate level and dress up a crypt and watch the PCs squirm. 

Treasure? Generally undead have little concern for the material things — quite the aesthetics, eh? But I’m sure you can find an approrpiate disease to afflict the PCs with. Filth fever is the gift that keeps on giving.

3. “Thief, get up here!”

One room should have a trap or skill challenge of some sort. The DMGs for both Third and Fourth editions have plenty of good ones to choose from. Just make it appropriate to the level of the PCs. One bit of advice, don’t make this challenge a game-breaker.  Maybe the trap protects a vault, but don’t use it as a roadblock to the rest of the adventure. The last thing you want is to have the PCs bested by the trap and give up exploring. 

Treasure? Add up all the XP of all the creatures defeated so far, assign a silver piece value to each and make the sum the amount behind the lock. It’s a formula with no basis on the economics of D&D, but strangely it works. Either that or place a pregenerated treasure, such as those listed in the Fourth edition treasure parcels, in the room.

4. “Is it OK to panic, yet?”

Find that one special monster, you know, the one a couple of levels higher than the PCs, the one with all the cool abilities, and use it here.  The more magical its nature, the better. Give it a helper of an appropriate level if you’re afraid the PCs will gang up on a solo monster too fast, but make sure the focus is on this really special monster.

Treasure? The remains of some hapless adventurer should be close by. Maybe there’s something in his pockets.

5. “Don’t tug on Superman’s cape.”

The last room contains the Big, Bad, Evil Guy (or Gal). He’s not happy, he’s got what you’re looking for, and he probably snarls a lot. (After all, he lives in this dungeon with the mooks and the creepy undead and that special monster).

Make the BBEG a mosntrous humanoid with class levels or an NPC a level higher than the PCs. All BBEG’s have sycophants, so add a monstrous humanoid and call him “Igor.”

Oh yeah, the BBEG’s also got a magic item of some value. Make sure you pick something nice, something he can use again and again on your hapless PCs. That way when they finally vanquish him (or her), the PC can say: “I got this at such-and-such a place.” 

Treasure? Hey, you just got a magic item. You want more? OK, roll randomly to determine which PC would best benefit from an item. Once that’s been selected, find something appropriate and hide it away in the BBEG’s stash.  Throw in some petty cash — gold and gems — and you’ve got an evening’s worth of entertainment.

What about a hook?

For an impromptu adventure, go with “Save the Cheerleader” or “Snatch the Dingus,” in other words, go after a person or thing of value that’s in the BBEG’s possession.  In my experience, there’s always some rich dude hanging out in the tavern waiting for some unscrupulous-looking adventurers to hire to retrieve it for a reward. 

Or something like that.