Time

A Few Facts Concerning GMT, UT, and the RGO - Explains the differences between several time systems.
http://www.apparent-wind.com/gmt-explained.html

A Walk Through Time - Evolution of timekeeping through the centuries.
http://physics.nist.gov/GenInt/Time/time.html

The Calendar - Summarizes the history of various calendars developed and used over the centuries.
http://www.skeptics.com.au/journal/calendar.htm

Z-Time - Article on the time at 0 degrees longitude. Covers the timezone origin, GMT, UTC, GCT, ZULU and JIG.
http://www.maybeck.com/ztime/

Calendar Zone - A categorized collection of calendar related sites.
http://www.calendarzone.com/

NPR : 'Seize the Daylight': A History of Clock Chaos - Benjamin Franklin first called for the government to tinker with clock hours in the 1780s. But it wasn't until World War I that the United States adopted daylight-saving time as a way to get more efficiency out of the day. "Seize the Daylight" Author David Prerau talks about the complicated politics and curious history of DST, and he shares an excerpt from his book. [4:54 streaming audio broadcast]
http://www.npr.org/templates/story/story.php?storyId=4572036

Calendar Studies - Information about calendar history and calendar reform.
http://www.hermetic.ch/cal_stud.htm

U.S. Time Zones - History of standard time in the U.S.
http://aa.usno.navy.mil/faq/docs/us_tzones

Infoplease: Daylight Saving Time - Information and history about Daylight Saving Time all over the world.
http://www.infoplease.com/spot/daylight1.html

Wikipedia: Time - Time is a common term for the experience of duration, and a fundamental quantity of measuring systems. Article explains time definitions, history of measurements, perceptions in religion, philosophy and science.
http://en.wikipedia.org/wiki/Time

Time - Provides descriptions of several standards of time.
http://scienceworld.wolfram.com/astronomy/Time.html

International Standard Date and Time Notation - An overview of the ISO 8601 notation for dates.
http://www.cl.cam.ac.uk/~mgk25/iso-time.html

Internet Encyclopedia of Philosophy: Time - Time has been studied for thousands of years. Nevertheless, many issues remain to be resolved. This article explores both what is now known about time and what is controversial and unresolved.
http://www.iep.utm.edu/t/time.htm

Time Zone and Daylight Saving Time Data - A directory of sites providing descriptions of civil timekeeping concepts, source code, databases, and maps.
http://www.twinsun.com/tz/tz-link.htm

United States Code - Weights, measures and standard time.
http://tycho.usno.navy.mil/260.html

English Calendar - Includes an ecclesiastical calendar and a section on old and new style dating.
http://www.albion.edu/english/calendar/

NIST Time and Frequency Division - The National Institute of Standards and Technology maintains time and frequency standards for the United States.
http://tf.nist.gov/

This Day In History - Today in history every day - often with pictures and sound.
http://www.history.com/this-day-in-history.do

Time FAQ - Frequently Asked Questions about time (from sci.astro news group)
http://www.faqs.org/faqs/astronomy/faq/part3/

Today's Calendar and Clock Page - Information on all things relating to calendars, dates, holidays, and time. Find today's date on several different cultural and religious calendars. Includes section on Celestial data, countdown clocks, and information on the dates past events.
http://www.ecben.net/calendar.shtml

A History of Time - Explains the importance of concept of time in the history of mathematics, science and measurement.
http://www-history.mcs.st-andrews.ac.uk/HistTopics/Time_1.html