Oxford Professor & Fellow of the Royal Society James Murray uses mathematical modelling to predict whether a marriage will survive or end in divorce, with 94% accuracy. His lecture to the Royal Society will be available for view on demand within two days.
posted by UbuRoivas on Mar 26, 2009 - 44 comments

Online Encyclopedia of Mathematics Edited by Michiel Hazewinkel (CWI, Amsterdam), and originaly published in dead tree form in 2002, now free to browse and poke into. [more inside]
posted by Iosephus on Aug 2, 2008 - 7 comments

Whether you want to learn to lace shoes, tie shoelaces, stop shoelaces from coming undone, calculate shoelace lengths or even repair aglets, Ian's Shoelace Site has the answer!
posted by Blazecock Pileon on Jun 27, 2008 - 22 comments

The Johnson Solids are a set of 92 semi-regular polyhedra, all of which are uniquely named and numbered. Except for the familiar square pyramid they all have exotic names like the Hebesphenomegacorona. A Hebesphenomegacorona in space. Number 26, the Gyrobifastigium, is unique in that if copies of itself are properly stacked together they will leave no gaps, thus making it the only space filling Johnson Solid.
posted by Tube on Oct 3, 2007 - 28 comments

Math Team Solves the Unsolvable E8
"If you thought writing calculations to describe 3-D objects in math class was hard, consider doing the same for one with 248 dimensions. Mathematicians call such an object E₈, a symmetrical structure whose mathematical calculation has long been considered an unsolvable problem. Yet an international team of math whizzes cracked E₈'s symmetrical code in a large-scale computing project, which produced about 60 gigabytes of data. If they were to show their handiwork on paper, the written equation would cover an area the size of Manhattan."
posted by ericb on Mar 19, 2007 - 67 comments

The Zero Saga contains a great deal of information about the concept of zero, and its relation to other numbers and concepts in mathematics. It was linked in Good Math, Bad Math; which contains a variety of other informative articles on the numbers that capture our imaginations. (Note: You may want to skip past part 4 of the Zero Saga, as it contains replies to the site, and as such should probably be at the bottom of the page. But, to compensate, the comments on Good Math are better than most blogs I've read.)
posted by Eideteker on Aug 3, 2006 - 11 comments

Norman Wildberger's New Trigonometry Dr Norman Wildberger has rewritten the arcane rules of trigonometry and eliminated sines, cosines and tangents from the trigonometric toolkit. The First chapter of his new book, Divine Proportions, is online (.pdf).
posted by Kwantsar on Sep 25, 2005 - 21 comments

Jim Loy's Mathematics Page is (among other things) a collection of interesting theorems (like Napoleon's Triangle theorem), thoughtful discussions of both simple and complex math, and geometric constructions (my personal favorite); the latter of which contains surprisingly-complex discussions on the trisection of angles, or the drawing of regular pentagons.

Similarly enthralling are the pages on Billiards (and the physics of), Astronomy (and the savants of), and Physics (and the Phlogiston Theory of), all of which are rife with illustrations and diagrams. See the homepage for much more.

If you like your geometric constructions big, try Zef Damen's Crop Circle Reconstructions.
posted by odinsdream on Sep 14, 2005 - 8 comments

Capturing the Unicorn : How two mathematicians helped the Met to digitally stitch together the Unicorn Tapestry. (via)
posted by dhruva on Apr 28, 2005 - 22 comments

Mathematics Awareness Month - April 2005: Essays, DVD, Links. Prior MAMs.
posted by Gyan on Apr 1, 2005 - 7 comments

Thinking Machine 4 explores the invisible, elusive nature of thought. Play chess against a transparent intelligence, its evolving thought process visible on the board before you.

From Martin Wattenberg (with Marek Walczak); they have been noted here before.
posted by e.e. coli on Oct 27, 2004 - 11 comments

The House With Too Many Perpundiculars
posted by DevilsAdvocate on Jul 13, 2004 - 8 comments

Recreational mathematics and fractal graphics continue to stimulate the mind and foster student interest in mathematics. Some favorite authors & books in this area include: Martin Gardner's books (like The Colossal Book of Mathematics and The Night is Large), Cliff Pickover's books (like The Mathematics of Oz and The Zen of Magic Squares), Calvin Clawson's Mathematical Mysteries, Ian Stewart's books and puzzles, and Ivars Peterson's writings (like Islands of Truth). What are your favorite books and web sites in this area for stretching the mind and eye?
posted by Morphic on Nov 1, 2002 - 25 comments

Mathematician Henrik Lenstra was intrigued by a blank space in he middle of a drawing by MC Escher. Over two years he managed to describe the mathematical structure of the drawing, project what should go in the missing space and produce an extraordanary animation of the result.
posted by alms on Aug 6, 2002 - 32 comments