Sites of Interest

Geometers Sketchpad

http://www.keypress.com/

Pi birthdates

http://www.facade.com/legacy/amiinpi/

Animated proof of the Pythagorean theorem.

http://www.nadn.navy.mil/MathDept/mdm/pyth.html

http://www.davis-inc.com/pythagor/proof2.html

http://SunSITE.UBC.CA/LivingMathematics/V001N01/UBCExamples/Pythagoras/pythagoras.html

More Pythagorean proofs

http://www.geom.umn.edu/~demo5337/Group3/proofs.html

http://forum.swarthmore.edu/~isaac/problems/pythagthm.html

This has many versions.

http://www.cut-the-knot.com/pythagoras