There are two modules in this distribution. Date::Doomsday calculates doomsday
for a particular year. Date::DayOfWeek uses the doomsday algorithm to
calculate the day of the week for any given date.

Doomsday is a cute little idea invented by Dr John Conway that makes it very
easy to figure out the day of the week for any date.

You can find out more about doomsday and related calculations at
http://www.interlog.com/~r937/doomsday.html