Basically, DF is huge ripoff of LOTR:
In first book, we have adventurer discover fortress that fell to HFS and have em fight tentacle demon and spirit of fire. They on survive because they pull lever and collapse bridge.
In seccond book, we have classical "no booze, bad food, slept in rain lately" tantrum spiral on orcs which is made more fun by aproaching siege.
Then we have good old siege of helms deep which included elven trade caravan stuck inside fortress for duration of siege.
And siege of Sarumans fortress which is result of not meeting tree quota by treehuggers. Building destroyers messed up his workshops a lot and he ended up turtled behind locked door. There was tiny tantrum by Grima and he ended up hammering Mayor so hard he flew out of window and land unconscious on weapon trap, which he triggered and where he died.
There, in third book we have goblin tower fall to food/loot related tantrum spiral, which started when they discovered that their Giant Cave Spider, a spider silk farm, got killed and that adventurer that did it dropped nice *tiny chainmail* that everyone wanted. Lucky for adventurers, their butcher was on break, so they only had to wait till everyone tantrumed to death.
Tolkien was lously DF player, it is like he never started proper food industry, and his orc/goblin fortresses obviously lacked great dining halls. :-/