We all know that fantasy worlds have a lot of interesting gadgets, odd technologies, and unusual weapons.
What is your favorite/most interesting piece of technology in your worlds? Or, if you haven't created a campaign, what unusual contraption would you like to make.

Personally, after watching the Mythbusters re-visit of the confederate rocket, I have the strange urge to let the orcs steal some dwarven technology, re-fit it, and build a guided missile...with meat as a fuel source.
I can't wait for this encounter:

Orc: "Fire the Meat Missile!"
Party: "Wait...WHAT?"

I imagine the look on their faces will be priceless.