Yes i know, its not really related to my site but I thought that the new cool category needs some articles and you´d probably enjoy it nevertheless. Best to use on co-workers, friends aso. All illusions are explained in detail, telling you exactly what will happen when you look at them.
Most involve movement which you can alter using buttons to change the effect. The illusions are divided into eight categories: Motion and Time, Luminance and Contrast, Color, Geometric- and Angle Illusions, Size Constancy, Cognitive- / Gestalt Effects and What’s special about faces?
Just head over to michaelbach.de and take a look at the optical illusions, you can also take a full tour.

Lock Optical Drives
Tour de France Live Tracker
Create Website Tours With Virtual Tour Software Amberjack
Easy Monitor Calibration
Pricelessware 2006 Freeware list
Firefox Web Browser Customization With AnyColor
[...] Ilusiones ópticas. Vía Ghacks. [...]