Here's more than five, in case you have already seen some before:
AnyBirthday http//www.anybirthday.com
A unique site - it has a database containing the birthdays of most adult Americans. Their paid service is awesome for adoptees - enter a first name and birth date, and it returns where they live.
"The Halfbakery is a communal database of original, fictitious inventions, edited by its users. It was created by people who like to speculate, both as a form of satire and as a form of creative expression."