How about something fun?

Check out this freaky illusion.  Basically you stare at the dot in the center of the picture for a few seconds and then mouse over the picture. The picture will look like it has normal coloring.  Now look away from the dot. Surprise!  The picture is actually black and white, but your eyes superimpose the photonegative of the coloring from the first picture making it seem colored.

Maybe it is cooler than it sounds.

Link via PlanetDan.