Dodecahedron Measures
I recently saw a newsgroup post from someone asking for the formulas of the surface area and volume for each of the five Platonic solids, given the side length. Having a little free time, I decided to work out one of the more difficult ones, the volume of a dodecahedron.

Geocadabra
Geocadabra is een wiskunde programma voor het gehele onderwijs: Dynamische vlakke meetkunde, Dynamische ruimtemeetkunde, Perspectief tekenen, Statistiek en kansrekening, Analyse van functies en krommen, 2e fase applicaties...

Isotropic | polyhedra
Here are templates for making paper models for each of the 5 Platonic solids and the 13 Archimedean semi-regular polyhedra.

Paper Models of Polyhedra
Polyhedra are beautiful 3-D geometrical figures that have fascinated philosophers, mathematicians and artists for millennia. On this site are more than eighty paper models available for free.

Polyhedra V1.0
This applet allows you to visualize the five regular polyhedra and their inclusions. The applet is customizable. It may be used to show a particular inclusion as in the previous image, but also to build interactively new inclusions.