Applets by Rich Schwartz Some fairly sophisticated applets including ones on elliptic curves, complex hyperbolic triangle groups, and hyperbolic tilings. 

Euclid's elements The entire collection of thirteen chapters from Euclid's book. 

Famous curves in mathematics A good collection of famous curves in mathematics. Information includes definition, brief history and a graph of the curve. Also allows the user to view several associated curves (like involute, inverse etc.). 

The Mathematica Book Graphics Gallery A collection of 2D and 3D graphs and figures from Mathematica's book, an introduction to Mathematica's graphics capabilities. 

Visual Geometry Pages Graphics and applets illustrating problems and concepts from differential geometry. 