The Attic Filled With Hay

A phenomenon usually noted by Liatai, but it seems to be universal among Dungeon Masters. Inevitably, when a Dungeon Master spends an incredibly long time planning for a session and tries to plan for every single possible course of action, the players choose the one course of action he or she has not planned for. This usually results in hasty improvisation, and sometimes ends up even better than the planned session!

Tarnade Keep

 * The event that gave the phenomenon its name.
 * Liatai spent the better part of a day creating Tarnade Keep using random dungeon cards, detailing rooms, adding monsters, and creating treasure stacks. (To date, Tarnade Keep is the dungeon with the most rooms the PCs have ever explored.) There was one room, however, that she did not flesh out entirely; in the guards' quarters, there was a room with a broken, moldy ladder and a trapdoor in the ceiling. Assuming that the players would just pass through the room and not linger, she did not even think to flesh out the attic.
 * Cue Team Stormblade entering and exploring the castle. When they reached the room with the trapdoor, they would not move on! They tried every trick in the book to open the trap door, from using a grappling hook to blasting it open with magic. Eventually, they managed to open it.
 * Scrambling, Liatai said that the room was dark. No problem; the PCs just lit a lantern for the one member of the party without low-light vision. Improvising, Liatai described the room as filled with hay, and started to add details as the PCs explored. Hence, the Attic Filled with Hay.
 * This attic proved to be one of the most remembered rooms in the whole castle, despite never being planned for in the first place.

It's Impossible to Lose PCs in the Mountains

 * During the undead plot, Team Stomblade witnessed an attack on Juben Reyen by Brent's forces in an attempt to steal some onyx pieces, which are required for creating zombies and skeletons. After defeating an owlbear skeleton and a chimera skeleton, the group was attacked by a band of assassins wielding drow poison. They succeeded in knocking out the PCs, and sent them downriver in a boat with no oars.
 * After rescuing the boat from taking a tumble down a waterfall, the team found themselves in the foothills of the Redbridge Mountains. They had never been that far west, so the area was new to them. Liatai had been attempting to get them to the western shores of Akellon, to have adventures there.
 * The PCs persisted, trying to get back to Castleton. They met with a group of gryphons, and asked them where the nearest settlement was. While gryphons can understand Common, they cannot speak it. Liatai described the gryphon raising a wing "in the direction of the setting sun," trying to point the way to Tresca, a coastal settlement. Hopefully, that would get them thinking that a city lay that way, and they would explore in that direction.
 * Liatai didn't count on DaSzab using logic she hadn't even thought of! He quickly asked whether the river was flowing toward or away from the sun's direction. Since the river flowed toward the sun, he deduced that they needed to head the other way, east, to get back to Castleton! Liatai SCRAMBLED. She threw fog and rain at them, to obscure their view of the sky; no problem. Zyr flew above the fog. She threw displacer beasts at them during the night; still no problem. She threw rapids at them as they tried going upstream; no problem, they crossed over into the swamps on the other side of the river and continued on foot!
 * Once the PCs returned to Castleton, they set the villains scrambling and put them on the defensive for the rest of the storyline, since they had been expecting a week free of adventurers and instead only got three days.

The Stray Storyline
-was full of these events...
 * The Drow Poison
 * Artemisia Coralline