Calendars, Time 

Calendar Converter
Convert any day into Julian, Gregorian, Hebrew, Islanic, Perdian, Mayan, Baha'i, Indian Civil, and French Republican calendars. Includes a useful overview of each calendar system. See also CalendarHome.com's version.

UVa Calendar
Everything that's going on in all Schools and Colleges at the University. Search by day, week, or keyword.

Earth Calendar
Find holidays and celebrations around the world by date, by country, or by religion. See also holidays and observances from Yahoo.

Ecclesiastical Calendar Calculator
Calculate Easter, Lent, Avent, Christmas, and associated moveable feasts thereof in both Western and Orthodox calendars.

New World Clock
Displays date and time from all 24 time zones simultaneously.

World Time Zones Maps
Search for local time in areas all over the world, and find information about time zones, Greenwich Mean Time, the history of time, and more.

NASA's world time zones map