@frauenfelder: I’m a scientist working on vision, and can recommend this website as a treasure trove of similar phenomena: http://michaelbach.de/ot/index.html
I particularly recommend motion-induced blindness (dots that you know are there disappear before your eyes), the lilac chaser illusion (stare at it for a while and all you’ll see is a green dot jumping around, except there is no green dot), and the particularly compelling demonstration of the motion aftereffect (look at your hand and it feels like things are crawling underneath your skin, look at your friend’s face and it’s hilarious).
Psychologists / neuroscientists love it when these illusions ‘fool’ us - it often tells us something about what the brain is doing computationally. The website above is maintained by a vision scientist and generally provides a referenced explanation of the illusions for if you want to find out more.
