In my lab at UC Santa Cruz, we used a laser cutter to carve our school logo into a pumpkin. One of the graduate students devised a rolling rig so that the distance to the surface of the pumpkin remained roughly constant, keeping the beam in focus. He made a video of the process seen at the link below.
Slashdot Mirror
http://apps.soe.ucsc.edu/elkaim/archives/000333.html