Language Log

http://languagelog.ldc.upenn.edu
language-related essays

languagehat.com

http://www.languagehat.com
essays, commments, links to language-related web sites, linguablogs, language resources, etc.

International Phonetics Association

http://www2.arts.gla.ac.uk/IPA/index.html
charts of the International Phonetics Alphabet

The Prime Pages (prime number research, records and resources)

http://primes.utm.edu/

Online Mathematics Textbooks

http://www.math.gatech.edu/%7Ecain/textbooks/onlinebooks.html
college-level textbooks available online for free!

Math Fun Facts!

http://www.math.hmc.edu/funfacts/
A collection of mathematical facts compiled by Professor Francis Su of Harvey Mudd College.

Fibonacci Numbers, the Golden section and the Golden String

http://www.mcs.surrey.ac.uk/Personal/R.Knott/Fibonacci/fib.html
fascinating Fibonacci facts and folklore

Mathematical Association of America

http://www.maa.org
matematical, people, history, fiction, humor (who knew math could be funny?), puzzles, and contests

The Fibonacci Association

http://www.mscs.dal.ca/Fibonacci
Find out more about the amazing Fibonacci numbers (1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, ...)

PiSpirals

http://www.joyofpi.com
Everything you ever wanted to know about the number pi.

The Prime Pages (prime number research, records and resources)

http://primes.utm.edu

Wolfram MathWorld: The Web's Most Extensive Mathematics Resource

http://mathworld.wolfram.com
Self-proclaimed most extensive mathematics resource on the web. Site created, developed, and nurtured by Dr. Eric Weisstein, who began compiling when he was a HS student.