Calendar Reform
To promote thinking about past and future calendar reforms

Calendar Studies
Articles on the Gregorian and Julian calendars, the ISO date format, the Julian day number system, the Maya calendar, the Goddess lunar calendar, the Liberalia Triday Calendar and C functions for date conversion; plus software for calendrical conversion.

Calendar Zone
Comprehensive categorized calendar catalog currently containing countless correlating connections & calzone recipes. Dates in Calendar are Closer Than They Appear! (Formerly CalendarLand)

Calendar of Lesbian, Gay and Bisexual Saints
Calendar of Lesbian, Gay and Bisexual Saints

CalendarHome.com
CalendarHome.com - this day in history, 10,000-year calendar,a store with hundreds of calendars, and hundreds of links.

Calendars and Their History
Calendars and their History

Calendars through the Ages
History and FAQ's of calendars, from ancient Rome to outer space. Including Julian, Gregorian, Jewish, Islamic, Chinese, and Mayan.

Clickable Calendars
A Clickable Calendar which displays interesting things that happened on each date. Just click a date.

Doomsday Algorithm for Day of Week
The Doomsday algorithm gives the day of the week for any date (and you can do it in your head).