ARTnatomy: Anatomical Basis of Facial Expression Learning Tool. See how all the different muscles in your face work. Flash interface; via Drawn!
What are nudibranchs? Jewels of the sea. Page after page of photographs of these squishy hermaphrodites.
These images remind us never to underestimate our opponent. -- The science behind the art (.pdf). Fractal art by way of bacteria growin' in a petri dish. A few more images here.