Calendars essentially evolved as organizational tools. As society became more complex, it was more convenient if days, week, months and years were coordinated. Different cultures created their own calendars, not all of them based on the same thing. For the most part, calendar and date-keeping systems evolved as either solar-based or lunar-based. Primitive man was able to notice and track the longest and shortest days of sunlight in the yearly cycle and those became some of the first holidays celebrated.

In modern times, calendars are a necessity for many people, helping to sort out which days we work from which days we don't, reminding us of important dates that would be best not forgotten  and they still work to organize large social and religious holidays.

Are you ready for 2010 yet?

Gregorian calendar - most of the world operates on this calendar, which marks the New Year as starting on January 1st.

Chinese New Year - also called the Lunar New Year.  This happens in January or early February, and falls on the first day of the first month according to the Chinese calendar.  In 2010 this date is February 14, 2010.

Jewish New Year - the Jewish calendar is also lunar-based and the New Year occurs in autumn.  The holiday is called Rosh Hashanah and happens on the first day of the month of Tishrei.  In 2009, it starts at sundown on September 18 and begins the Jewish year 5770.

Pagan/Wiccan New Year - the holiday of Samhain, which takes place on October 31st is when Neo-Pagans and Wiccans mark the turn of the wheel.