Imagediv
imagediv is exactly as the name itself suggests: an image constructed of divs. That in itself is not particularly spectacular (really), but what sets it apart from other things of the sort is that it pumps out pure, 100% valid XHTML and CSS to the browser. And, of course, a bunch of divs that are pixel-perfect to the orignal GIF, JPG, or PNG image.
My second delve into anything to do with the GD library in PHP code.