well, i suppose this would be the topic to talk about my most recent, and best fort falling.
i happened to have this place running for 12 years at 20 fps with 200+ dwarves. hella stuff, dwarves with bling. pretty much everything. then, a forgotten beast came through the cavern. a slathering worm with deadly dust. he charged into my mines, attacking a small party of civilians eating at a stored food stockpile. Several explosions later, and a civilian miner destroying it with a pick, 6 dwarves died, and 4 were...blasted with this dust. I checked them, they seemed fine. The bodies were buried, and things were nice. Then, I noticed the dwarf that killed the beast was numb, and now paralyzed. The sickness had begun. When a victim touched anything with extract on it (which was oddly a lot of things....damn wells...), they would be stricken with varying degrees of nervous system rot, to partial numbness, to deadly respiratory system paralysis.
Through the wells and the horrible butchery my hospital had become, around 75 of the dwarves were exposed, and the rest were in danger. I, having been bored with the fort, chose to deploy a self-destruct mechanism. It was a simple act, the dwarven caravan had arrived, and I chose my awesome ass squad to kill them. I also began to release small reservoirs of magma, setting the natural vegetation in my fortress's main floor on fire. I locked the door on them all, let the fire burn, and the slaughter begin. It was easily the most fun I have ever had. Dwarves would run down the hall, drop two dwarves with kicks, then have his brains bashed out by a flaming dwarf with a silver scourge. Fire, smoke, dodging into my magma dodge-this trap, the sickness, dwarves started dying by the score.
It finally reached the point where there was about 20 dwarves left in the hospital, some the last carriers of the extract, mostly the doctors who worked almost the entire full half year this happened. Others injured in the battle. Only two militia remained, a Hammerdwarf named Lokum. She had 180+ notable kills, and had slaughtered around 60 dwarves in the chaos. The other, Bim, a Speardwarf, was the leader of the training squad, a skilled fighter but with no combat experience. He had been in the hospital for some face rot, and had not slaughtered any fellow dwarves. Beforehand, he was a well loved and kind dwarf, who had trained Lokum, and all of my other militia in his combat school. The last remaining doctor, before succumbing to the disease himself, managed to remove his rotten eyes, yet not destroy Bim's vision. Before the fires reached the hospital, Bim rose, and charged Lokum. She was caught off guard, and the two began to battle across my main factory floor, surrounded by fire and the bodies of their former countrydwarves. For the first time in almost a decade, Lokum's blood was drawn by the thrust of an candy spear. The two battled for almost 5 pages before Lokum began to retreat, while still blocking, to the upstairs exit, and my dodge-this magma trap. They fought, quite literally blow for blow for 2 pages of combat report before reaching the magma trap, and a sudden strike by Bim. This strike was just that x4 luck for masterpiece, and went through Lokum's heart. As a final gesture, before Lokum died, Bim charged her, and knocked her back, and over a fall, straight down to magma, where she died at the bottom of 5 z-levels of 7/7 magma.
Bim rested in the hallway, his injuries almost certainly fatal even with a team of doctors. He, however, had a front row seat to the entire fortress burning down, and the death of all but 5 dwarves, who were stumbling around, burnt horribly and bleeding, and eventually collapsed, 2 died of blood loss, 3 died of infection.
It was epic.