Some links I like.
The Program of Mathematics Education
MacTutor History of Mathematics Site -- St. Andrew's University
Math Forum (alias Geometry Forum)
Assignment 1: Exploring the Sine Wave |
Assignment 2: A Look at Quadratics |
Assignment 3: The xb-plane |
Assignment 4: Exploration of the Centroid (Six Smaller Triangles) |
Assignment 5: GSP Script Library |
Assignment 6: How to Make a Parabola |
Assignment 7: Tangent Circles |
Assignment 8: Properties of the Orthocenter |
Assignment 9: Pedal Triangles |
Assignment 10: Investigating Parametric Functions |
Assignment 11: Polar Equations |
Assignment 12: Using Spreadsheets |