Shocktoberfest, a haunted house park in Pennsylvania, is offering a Naked and Scared Challenge this year.

The Naked and Scared Challenge allows participants to go through the
Unknown Haunted House Nude or Prude (either totally nude or with
underwear).  It takes place at the end of the night after all customers
have gone through the attraction.  Participants must be 18 years of age
or older and must sign a waiver.  Participants undress in a semi-private
preshow building, experience the Unknown Haunted House, and then exist
into a semi-private fenced courtyard where they will get dressed. 
Participants are never in view of minors or non-participating customers.

Naked and Scared Challenge is not offered on Sundays.

Calling it a "challenge" makes it sound like there's some sort of prize, but there really isn't. Unless you count seeing a bunch of other people naked a prize. If that's the case... EVERYONE WINS!

Also, I love that it's not offered on Sunday. Wouldn't want to offend The Lord.