Three141, a BBP Ruby implementation and a portal about Pi
- A Ruby implementation of BBP (Bailey-Borwein-Plouffe formula) and a portal about the Pi. The BBP formula calculates the nth digit of pi without having to retain all the previous digits.
- http://www.314159265358979323846264338327950288419716939937510.net

Calculating Pi
- An open source endeavor for the calculation of this constant. Describes the project, the implemented algorithms for calculatinon and software downloads.
- http://sourceforge.net/projects/projectpi/

Pi-Dye : Pi and Math T-Shirts and Gifts
- Pi and math gifts, t-shirts, clocks, and mugs. Includes some pi news.
- http://www.pidye.com/thestorezone/index.php

The Pi Song
- Written by Joel Gilmore. (Sung to the tune of Supercalifragilisticexpialidocious.)
- http://www.physics.uq.edu.au/people/gilmore/humour/the-pi-song/

The Ridiculously Enhanced Pi Page
- Information on links for Pi Day.
- http://www.exploratorium.edu/pi/

A Slice of Pi Home Page
- Features an historic overview of the discovery and estimate methods of pi. formula expressions, and the first 100,000 digits. Some pages use a Geometer's Sketchpad program.
- http://www.geom.uiuc.edu/~huberty/math5337/groupe/welcome.html

The Pi Pages
- Information on Pi, its history, its future, and the people involved in its calculations.
- http://oldweb.cecm.sfu.ca/pi/pi.html

Pi, Pi, Mathematical Pi
- Parody of the song "Bye Bye Miss American Pie" elaborating on the history of pi.
- http://www.vvc.edu/ph/TonerS/mathpi.html

Your Piece of the Pi
- This site describes pi's history, characteristics, and application. It also includes a distributed computing application for finding a large number of digits.
- http://library.thinkquest.org/C0110195

Pi Approximation Day
- 22/7 - that is, July 22. For the past few years, people at Chalmers University have celebrated it.
- http://www.rebas.se/humor/piapprox.shtml

Buffon's Needle
- An analysis of its relation to Pi and a simulation by George Reese.
- http://www.mste.uiuc.edu/reese/buffon/buffon.html

Fun With Pi
- A Topica email list. Archives readable by anyone.
- http://lists.topica.com/lists/funwithpi@igc.topica.com/

Indiana Pi Bill
- Bill proposing new value of pi.
- http://tafkac.org/legal/indiana_pi_bill.html

Pi Land
- Fun activities, a Pi trivia game and a Trainer for digit memorization. Pi poetry, artwork, and photography, calculations, digits and book reviews.
- http://www.eveandersson.com/pi/

Ask Dr. Math: About Pi
- Explains what the constant is and a brief history. Includes resource links.
- http://mathforum.org/dr.math/faq/faq.pi.html

A New Approach to the Universal Constant "pi"
- A text that tries to prove that pi is 3.1416 exactly.
- http://alkyone.com/mak-pi-gr/en/

Pi Patterns
- Images and illustrations created by using the digits of the circle constant.
- http://www.antigravitypress.com/Math/pi/

Elias' Pi Page
- Includes Pi in the Binary number system, Pi as a sound file and Pi shown in different images.
- http://www.befria.nu/elias/pi/

Lucy Scale Developments
- Pitch, Pi, and other musical paradoxes.
- http://www.harmonics.com/lucy/ltindex.html

Ask Dr. Math - Pi
- Dr Math answers over 60 questions submitted by people about pi including questions on the Bible's relationship to it and its relationship to trigonometry.
- http://mathforum.org/dr.math/tocs/pi.middle.html

Ancient Pi: Knowers of the Universe
- The concept of pi refers to the constant ratio of the diameter:circumference of any circle; irrespective of the number of degrees contained within that circle. An article in the "Science in Ancient Artwork"-Series by Charles William Johnson.
- http://www.earthmatrix.com/ancient/pi.htm

The Magic Piworld
- Provides generated pictures and personal signs out of digits of Pi. Also a Picture Gallery, PiSign, PiPhonie.
- http://www.piworld.de/piworld/mpw_home.htm

Pi World Ranking List
- Every sport has its championship. Every sport has its world ranking list. For many who like to memorize numbers, PI is the ultimate number, and it makes sense to create a list for people to get in touch and learn where they stand in the world of memoriz
- http://www.pi-world-ranking-list.com/

The Uselessness of Pi and its Irrational Friends
- Clubs, links, memorizing technique, records, art, and programs.
- http://www.go2net.com/internet/useless/useless/pi.html

Earth Mysteries : Notes on Pi
- An introduction to the number Pi and its history.
- http://witcombe.sbc.edu/earthmysteries/EMPi.html

Paul's Page of Pi
- Includes introduction on why people would want to calculate Pi, four methods for calculating it, over 8000 digits, poems and music.
- http://www.escape.com/~paulg53/math/pi.html

A Common Book of Pi
- Includes a brief history, a page with different formulas and a list of references.
- http://personal.bgsu.edu/~carother/pi/Pi1.html

History and Philosophy of Pi
- Probably no symbol of infinity in mathematics has evoked as much mystery, romanticism, misconception and human interest as the number and Greek letter of Pi. Interesting facts and trivia about Pi.
- http://briantaylor.com/Pi.htm

Pi Through the Ages
- History.
- http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/Pi_through_the_ages.html

How Stuff Works: Pi
- Animated graphic helps to explain Pi and the different ways of calculating Pi, with some related links.
- http://www.howstuffworks.com/pi.htm

Pi Memorama
- Includes a program that teaches Pi for the Mac, a page on why people learn to recite Pi and pages on how to memorise Pi.
- http://www.ac.wwu.edu/~mnaylor/pi.html

A Tribute to Pi
- Club and information.
- http://www.acc.umu.se/~olletg/pi/tribute.html

The Pi Trivia Game
- History, math, and physics questions.
- http://eveander.com/trivia/

The Joy of Pi
- Book, digits, links, facts, and quote.
- http://www.joyofpi.com/