Visitors are treated to a frightening experience as they make their way through historic Fort Knox’s dark passageways where they encounter ghosts, goblins, ghouls and other indescribable scenes of the macabre. Fright at the Fort was not held in 2005, but attracted over 10,000 visitors in 2004.The Fort will also offer a "low-Fright children's day" the Saturday before Halloween.
The event will take place the last two Fridays and Saturdays, October 20‚ 21 and 27, 28, from 5:30 p.m. until 9 p.m. (visitors are asked to arrive by 8:30 p.m. and children must be accompanied by an adult), admission to Fright is $5 per person. [source]
I remember going to Fort Knox when I was a little kid and finding it creepy even without the ghosts and ghouls.
The photo above is from the Flickr photostream of Elle Michelin. For more eerie images of the fort, see the collections of Night Owl City and cottergarage.