This is a rumor which I heard from an Intercontinental Hotels Group exec last week. The story goes that Christian evangelicals put money into hotel bibles, in the hope that people will open and look through the bible in the hope of finding the money. If there is no money there, well the rumor had the effect that the person has opened the bible and looked through it, and maybe they will read part of it. If the money is there, then they have given someone a gift, and also the person may well read the page in which the money was found (or maybe not).
Is this true, or just a rumor? I guess I am playing a part in promoting the rumor here with this blog post.
Snopes.com tracks the history of this particular rumor, which interestingly goes back to the 1950s, and exists in Jewish as well as Christian mythology.