If you were breathing in the 90's you remember Magic Eyes! I forgot how cool these were... I found a bunch online and posted them, Click on each to get a larger sized image.
If you don't remember, look at the picture and let it go out of focus, the trick is it only works when your depth perception isn't focused. You will see a 3D image in the flat picture, the longer you stare the more into focus the "hidden" picture comes. Be the first to post a comment with all the hidden pictures and you get bragging rights.