Yeah I know, silly of me to talk about it, but I just gotta gush about it so what the hell.
My fort's been running about at 9 FPS or so, and things have been going smoothly. My Divine Quarter project is well under construction, I have over 200 dwarves well-taken-care-of, my nobles are satisfied easily, and in general I turn on the game and let it run, occasionally giving a dwarf an order while the others idle and such.
So I turn on the game, and maybe a minute passes before suddenly one of my hunters is ambushed by goblins! I immediately tell all dwarves to get in the fort except my three ten-dwarf military squads, who go out there to fight. When the first speardwarf arrives he enters a martial trance at once. The other dwarves catch up soon, and one gob gets away, bleeding from the lower body. Something tells me he won't be having kids... another gob ALMOST gets away, but a swordsdwarf catches the gob JUST as he reaches the map edge. Military starts heading back to train.... and a human diplomat arrives on the nearby map edge, in time to see all the bodies.
Then, as the military starts heading back, another ambush pops up, right on top of my military! Needless to say, the goblins are slaughtered to the last being, all of it leaving a bloody pool in the area (with an amusing bloody path that the one gob took to get away). Then the rain arrives to wash away the blood, as a thief is spotted, who immediately runs off. We let him go. Then a caravan arrives to trade. And finally my woodcutter gets taken by a mood.
Sometimes a well-run fort moves slowly and unexcitedly.
Other times... it gets really busy. And fun.
In the more traditional sense, that is.