I spent my whole prep period today playing with a site I hadn't seen before: PHYSICS 2000 @ http://www.colorado.edu/physics/2000/index.pl?Page=cover.html. I need to spend some more time there. I would love to know if someone has lessons that they are currently using that take students to the applets. I am especially interested in using the applets for the periodic table, electromagnetic radiation and half-life radioactivity. I will share anything I come up with.