This site offers a few games and simulations for algebra, algebra 2, trigonometry and geometry classes. These activites/simulations offer great visuals for instructing.
Animated conic sections using a double cone. Could be used to show all conic sections in geometry, as well as the degenerate possibilities in algebra 2
Great site as a reference for geometry students and instructors. Offers dynamic interactive math applets. Provides thorough definitions and visual aides.