Every year, math enthusiasts everywhere celebrate pi, a celebrity among mathematical constants, on 3/14, also known as Pi Day. Pi is the symbol for the ratio of the circumference of a circle to its diameter. Whatever the size of a circle, if you divide its circumference by its diameter, you will always get 3.14159..., better known as pi.
Check out this page full of articles and websites to explore, and be sure to follow NCTM on Twitter to see exclusive Pi Day images this Thursday!
http://www.nctm.org/resources/content.aspx?id=2147483830
See http://www.scientificamerican.com/article.cfm?id=what-is-pi-and-how-did-it for information about pi.
More information about activities for Pi Day: http://www.edutopia.org/blog/pi-day-lesson-plans-matthew-davis