See title.
Mine's managed two.
One was fairly standard; a few goblins broke the line of defenders and got into the fortress, but were beaten to death by the civilians. Never doubt the power of the dwarven dog pile.
The other one happened when the first caravan (new fort) left on bad terms (I swear, that diplomat was a whiny little elf) and I took a look at the stocks to find that there was no plump helmet wine, no plump helmet seeds, and no plump helmets. That winter was a hard one... a lot of rodents were eaten, a few migrants died of dehydration, and more than one violent riot was put to rest by the militia. Come spring, we began to forage outside for food, though all we really got was a lot of blade weed... we also hunted and consumed badgers. Most of them barely made it to the stockpiles before they were set upon, let alone being cooked. Children continued to die of malnourishment. Tantrums ran rampant. One of the milita starved to death in his hospital bed after being injured during a riot involving a legendary miner. Finally, in mid summer, armageddon broke out with a tantrum spiral brought on by the consumption of someone's pet cat. The survivors were most of the S7, minus my mason and one of the farmers, as well as five members of the militia, much of the hospital staff, and a few kids. They survived by eating fisher berries gathered from outside, drinking water, and partying nonstop to stave off insanity. At last, Autumn came, and these were the few dwarves left to meet the caravans. Nevertheless, we wheeled out the stone crafts to the trade depot. At last, the plump helmets!
EDIT: Should also say that we ran out of cave wheat and rock nuts, and didn't have the capacity to get anything out of the sweet pods.
Then he charged me all my stuff for ten plump helmets and threatened to walk out again if I refused.
Bastard.