Yesterday I received a bar of black acetal I bought through eBay. Just for fun, I put it on my desk and set one of my medium-power (200mW) lasers to intersect an edge. It took a moment (the laser isn't well focused), but it cut a 0.006" pinhole through about 0.110" of acetal. That's small enough that you have to line your eye up with it spang-on to see light through the pinhole.
A higher-power cutter, some fume venting, and I won't have to saw off the chunks when I need some for workpieces.
Cool! Or perhaps, Hot!