There's a site I found awhile back and I've mentioned to some of you before -- somebody took Photoshop, and with some work managed to remove all the people from various pornographic images. When you look at the various bland indoor settings, you can tell that something's odd, and it's obvious that it's meant to fade into the background, but you wouldn't have guessed exactly what's wrong.
There are various other cute things you can do by taking a work of art or literature and removing "the point". They vary widely in quality, as you'd expect. Many become something completely different.