Countdown  
   Calculate the exact time in days, hours, minutes and seconds from now until your birthday or any other event.
   http://www.spiders.com/countdown/

Daylight Saving Time  
   Why do we use daylight savings time and who invented it?
   http://www.mrdowling.com/601-daylight.html

International Standard Date and Time Notation  
   International Standard ISO 8601 specifies numeric representations of date and time. It helps to avoid confusion caused by the many different national notations.
   http://www.cl.cam.ac.uk/~mgk25/iso-time.html

Latitude and Longitude  
   Introduction to latitude and longitude, a way of calculating exactly where you are anyplace on earth and a way to tell time.
   http://www-spof.gsfc.nasa.gov/stargaze/Slatlong.htm

Make Your Own Star Clock  
   Learn how to tell time by finding constellations in the night sky.
   http://www.lhs.berkeley.edu/StarClock/starclockprintout.html

Making a Sun Clock  
   Before there were clocks, people used shadows to tell time. Learn how to make your own sun clock!
   http://www.exploratorium.edu/science_explorer/sunclock.html

Making a Horizontal Sundial  
   Learn how to make a sundial. Instructions are for beginners, intermediate, or advanced, and work for either the northern or southern hemispheres.
   http://www.lmsal.com/YPOP/Classroom/Lessons/Sundials/sundials.html

Time  
   Just how do we measure time and what has Greenwich England got to do with it?
   http://www.mrdowling.com/601-time.html

Time Travel  
   Is time travel possible? See what Carl Sagan and Einstein had to say about time travel in this NOVA special.
   http://www.pbs.org/wgbh/nova/time/

A Walk Through Time  
   An illustrated history of timekeeping from ancient times to the present.
   http://physics.nist.gov/GenInt/Time/time.html

What Time is it!  
   Gives the current time, synchronized by NIST. Close to 100 different time zones supported, as well as the ability to select the default time zone.
   http://www.whattimeisit.com/

World Time Converter  
   Provides online times converter and brief information about GMT/UTC.
   http://www.gkindia.com/bitsol_time/

Local Times Around the World  
   Find out what time it is anywhere in the world.
   http://www.timeanddate.com/worldclock/