My ever-inventive partner Matt built this 3-axis mill essentially from scratch right in our living room. I did not even know what a mill was before a few months ago, but supposedly this one can be used for light engraving.
There are two flat Plexiglas plates that move in the X and Y directions, and another structural element that moves up and down along the Z axis. There are three motors hooked up to wires that go to a computer-based control system. On the computer you can use software to draw or write the text/images you want engraved, and then you just place the material onto the proper part of the mill and it will trace out the specified pattern.
Matt does not have any actual "internet presence" -- no blogs or flickr or Youtube accounts or anything -- but this was just too cool NOT to put online, so I did it. :)