This particular device has probably earned itself the lowest safety rating of any of my goblin traps, but it's been fun nonetheless. I present The Device:
http://mkv25.net/dfma/poi-6019-mainentrancePros:
* Smooshes goblins into jelly
* No messy cleanup
* Hurls pesky elven traders as far as you want
* Extremely large target area
Cons:
* Takes forever to build
* Frequently kills dwarves who are in the wrong place at the wrong time
* Timing on The Lever can be difficult
For those too lazy to click the link, the entrance to the fort is completely surrounded by approximately 90 drawbridges (maximum sized, using 26 rock blocks each). All the bridges are connected to a lever. Pull the lever, goblins get hurled. Pull it again, goblins get pulverized.
The device itself has caused a few fatal accidents (and at least one not-so-accidental accident), but oddly enough the #1 dwarf killer this time around as been the pack of wild camels. I dug a moat around the entire border of the map early on, but these camels were trapped within the borders. They bred... oh, they bred. And then they started interrupting work on The Device.
They had to be dealt with, of course. A single axedwarf should have been sufficient, but fortune conspired against him. Maybe it was his lack of armor? Anyway, his axe got stuck in the 2nd camel, so he resorted to wrestling the poor beast. It must have kicked him right in the head, and he went down.
Unfortunately the camel was not injured badly enough to die from its wounds, so it was wandering all over the map - with my only axe! Without an anvil I couldn't forge another one, so it had to be retrieved at any cost...
Long story short, two wrestlers later and I got my axe back. The rest of the camels were dispatched without incident.