Colloquium of Visual Illusion
A gallery of classic and original visual illusions
Color vision demonstrations
dealing with issues of invariance, by Hans Irtel.
Exploratorium on-line exhibits
Great interactive demonstrations in experimental psychology and psychophysics, from the Exploratorium science museum in San Francisco
Impossible world
Depictions of impossible figures. Optical illusions include wireframe and greyscale images, animation, and links.
Motion perception tutorial
by George Mather
Myron Braunstein's demos
Interesting cases of how we perceive structure from motion.
Visual physiology interactive tutorial
by George Mather. Includes demonstrations of many important effects and illusions.