WWW Resources for High School Teachers

General Mathematics Sites

The Math Forum is a large, well-organized site with resources for teachers and students at all levels. Among many interesting things there, you can find Teacher2Teacher, which consists of online discussions among teachers, and a list of Math Ideas for Science Fair Projects. There is also a set of Problems of the Week for various levels and a page with links to Spanish language math resources. The Math Forum is updated frequently, so it's worth checking now and then to see what's new.
Frequently Asked Questions in Mathematics, anyone?

For some colorful examples of the 17 wallpaper groups, look here. There are more wallpaper patterns here..
The artwork of M.C. Escher is closely related to several mathematical ideas, including symmetry. The "Official M.C. Escher Website" is a good place to start. It has a page of links to other sites, mostly commercial (with flashy advertising). These include one with a "minitext", which is organized along mathematical lines. There is also a site with higher resolution versions of some of his art.
I just found a site on Mathematical Patterns in African American Hairstyles.
Here's a Math Forum page on The Art of Oriental Carpets.

The Geometry Center was a research and education center at the University of Minnesota. It has closed, but its web site still has a lot of interesting materials. In particular, I like The Gallery of Interactive Geometry.

Philemon Clarke at AES told me about www.regentsprep.org, which is maintained by the Oswego City School District. It has information for students and teachers about the topics for each exam as well as lesson pages and study guides.

I found some online curriculum units, Environmental Responsibility and The Environment Around Me, from the Yale-New Haven Teachers Institute. They are long, but might have useful ideas in them.