math

http://blogs.scientificamerican.com/roots-of-unity/2013/09/12/10-trig-functions-youve-never-heard-of/ Trig functions long forgotten to time.

http://ipsur.org/ An introductory textbook to statistics and the R programming language.

http://www.gutenberg.org/wiki/Mathematics_%28Bookshelf%29 Project Gutenberg has started typesetting out-of-print math books in LaTeX.

http://thevirtuosi.blogspot.com/2011/10/linear-theory-of-battleship.html A look at a system that estimates the probability of ship placements in Battleship.

http://www.youtube.com/watch?v=vlDoSv6uDKQ UCLA mathematicians have created a system for automatically arranging furniture.

http://betterexplained.com/articles/a-visual-intuitive-guide-to-imaginary-numbers/ An explanation of how imaginary numbers work as a rotation.

http://en.wikipedia.org/wiki/Braess%27s_paradox It turns out that adding road capacity can sometimes cause worse travel times.

http://www.cabinetmagazine.org/issues/16/crocheting.php An interview with two professors who crocheted hyperbolic shapes to demonstrate their properties.

http://blog.wolfram.com/2010/08/13/25-best-hangman-words/ This post comes up with a method to find the hardest to guess hangman words and gives a list.

http://www.youtube.com/watch?v=P9dpTTpjymE A calculus parody of I Will Survive.