Conversion Calculator
http://www.infoplease.com/pages/unitconversion.html
The Conversion Calculator can be applied in different aspects, just like Length/Distance, Area, Volume, Weights/Mass, Temperature, Cooking and Time.

Distance Calculator
http://www.infoplease.com/atlas/calculate-distance.html
This tool allows you to find the locations of parks, mountain peaks, famous buildings and monuments, mines, dams, schools, and much more.

Perpetual Calender
http://www.infoplease.com/calendar.php
You can check for the history on a certain day and find out the events occured in certain year.

Place Finder
http://www.infoplease.com/atlas/latitude-longitude.html
Find distances between cities/towns, land features, and more

The Spelling Checker
http://www.infoplease.com/spellcheck
The Infoplease spelling checker combines spelling help with the dictionary and thesaurus

Time and date.com
http://www.timeanddate.com/
Time and date website provides the Time Zone calender, Sun and Moon calculator, the calender for any year. You can trace back to the date 1000 year before!

Year-by-Year
http://www.infoplease.com/yearbyyear.html
You can use the Year-by-Year calender to see any calender in the future or back as far as 1583.