Look closely. Or not too closely ... and you'll see an optical illusion on the album sleeves of the band Soulwax. (Need a hint? Don't look directly at your monitor - view the picture above at an angle).
The Monkey Buddha has one more example: Link | Another Phantom Message - Thanks Paul Micarelli!
Update 8/1/08 - Sleevage featured this first (they also have many more cool album covers) - thanks Ashley Ringrose!
SOULWAX
ANY
MINUTE
NOW
I did the glasses thing too. It was weird, because I could see it clearly, then when I put my glasses back on, I could still see it for a second or two before it became unreadable.
The weirdest thing is that it distorts like a lens as I move backwards and forwards. Freaky!
I used a Firefox mouse gesture to reduce the image size. At half-size, the words are apparent with no effort.
Cool! How about an app that can do this with any text you supply to create an image? I'd download that... freeware.
This illusion works the opposite way - the closer you are, the harder it is to see.
http://www.batterbrown.com/
Mine's easier to see, but I really dig that soulwax one.
But I found it easiest to slide the glasses to the tip of my nose and look through them.