The Internet Archive is featuring free access to rich media (moving images, music, audio or texts)

The National Science Foundation always has interesting speeches and lectures.

"Graphviz is open source graph visualization software. Graph visualization is a way of representing structural information as diagrams of abstract graphs and networks." If you like mind-maps or visual thinking, check out their gallery.

'Controlling hostile crowds' with laser guns? Could a temporary blindness lead to total blindness?