Humper Monkey’s Ghost Story has just about everything you could ask for in a haunted building story. Inexplicable occurrences, dead bodies, a Nazi past, and lots of general creepiness. Oh, and it’s theoretically true. It seems to have originally been posted on Something Awful.
Be forewarned that it’s really long; plan to set aside an hour or two if you want to read the whole thing, as it’s easily novella length.
And, if that weren’t enough, there seems to be more to the story here. It gets a bit less subtle.
I also hope Humper-Monkey gets a cut of this, and it’s not just somebody ripping him off.