This article is from the Libraries FAQ, by Anthony Wilson firstname.lastname@example.org with numerous contributions by others.
Four. One to install the bulb and three to test it in staff mode for
three months before the patrons get to use the light.
Ok, I know it's bad, but the New Jersey State Library
http://www.state.nj.us/statelibrary/lbhumtoc.htm , invites you to
visit and submit your own library jokes.
For more laughs, take a look at IFLANET Library Humour,
IFLANET also has an interesting collection of library quotes:
Do you want to know more about strange patrons, strange things found
in books, and strange smells in the stacks? See Hypatia's Humorous
Library Tales, by Jenny "the Circ Girl",
"If you had any idea what was going on in the minds of the seemingly
normal people around you all day, you'd run for your life."