PDFs of individual Geometry lessons, largely aligned with Michael Serra's Discovering Geometry textbook.
GeoGebra's free dynamic Geometry canvas is an amazing way to visualize and experiment with Euclidean Geometry concepts.
A collection of videos that demonstrate basic compass constructions.
Use a virtual compass to create compass constructions. (Requires browser Java support.)
Interactive two-column proofs tool with a focus on triangle congruency theorems/conjectures.
Interactive two-column proofs tool, organized by topic and complexity.
A collection of AP Computer Science lessons aligned with Litvin & Litvin's Java Methods.