Haven't done an OA post for quite a while now. Time to put up something!
Here's a map I made of Kakegawa Castle, in Shizuoka Prefecture, Japan. I've been to this castle, and one of the brochures I picked up there had floor plans of the place. Of course, I turned it into an adventure location. I ran the adventure with the Evansville Group in the short 1E/2E hybrid OA game I ran for them. They had a mission to assassinate the lord of the castle, a Kensei, and preferably do it stealthily. They were doing fine, until one of the ninja, who'd climbed the roofs to get to the top of the donjon used a nage-teppo (hand grenade) to take out some guards! Despite the alarm being sounded, they managed to off the sword master and escape.
Quite a while back, I decided to re-do the map as a computer image. Here's what I came up with: