Guide of Modos
GM: Ravenshiv, when you peek behind the door, the first thing you notice about the next dungeon room is the smell. It's stale, as if the roasty air from the wood-fires and torches of the previous rooms hasn't reached here. (Rolls on monster table) you get the feeling that no one uses this room.
Ravenshiv: what is it, a broom closet? Empty pantry? Wait, I know. Yoga studio. These orcs look a little out of shape. How big is it?
GM: (Rolls on rooms table) it's too dark to see. Yanniweh's torch is twenty-five meters behind you, and around a corner.
Yanni: And I didn't want you to go alone in the first place.
Ravenshiv: I didn't become a great treasure hunter by needing backup everywhere I went. Anyway, no lock, no creatures, no fire. No reason to trap this room. I'm going in.
GM: (Rolls on traps table) nope. No reason at all. Definitely no reason for a bear trap to be lying on the ground in front of your foot. Roll physical to react!
Ravenshiv: Oh, this could hurt. I'll use Detect to hopefully add some hair-sensitivity to my poor, soft-leather-wrapped foot. (Rolls) 13?
GM: Snap! You gain a Flaw: Bear Trap on Foot. (Rolls on peril table) uh oh. And the noise of the clamp on your foot, whether or not you decided to scream, must have awakened something in the room. Because you...(has to reconcile the appearance of a subordinate BBEG with the no-monster roll earlier) hear some metal scraping, and the sound of rock crumbling from a short distance ahead of you in the dark. Almost like a wall being torn down!
Lend me your experience! I want to put some random generators in a game module. I know they've been around for a while - I still have the loose-leaf random monster encounter tables from AD&D 2e. But have you seen or used a random dungeon generator? Would you run a dungeon crawl without knowing what's in the dungeon?
What if a GM's role changes from planning out encounters to challenge PCs, to rationalizing unknown elements in a dungeon and attempting to keep the party alive in a plausible way?
Let's hear your good, bad, and ugly stories about random generators and GM surprises!