Wikimedia
Wikipedia: Tzolk'in
The Tzolkin is another name for the Maya calendar. The meanings of the symbols on the Tzolk'in and various interpretations that are given to the calendar are outlined here.
University of St. Andrews (UK)
University of St. Andrews: Mayan Mathematics
After a historical introduction, this site from the University of St. Andrews provides information about the mathematics of the Maya Civilization and shows just how advanced they were.
Khan Academy
Khan Academy: Timekeeping
Why do we need calendars and clocks? To survive in this complex society, you need to track what others are doing and when they're doing it. You also need to know what's happening in the natural world. This article discusses how/why...
Other
Mayan Calendar
While brief, this simple explanation of the Mayan calendar may clarify for some how its two cycles work together.
Other
The Maya Calendar: A Converter
Gives the Mayan days and months. In addition, a Java Applet is included which will convert any date (Gregorian calendar) to its corresponding Mayan date.
