On Instructables, CaseyBorders's recipe for making stained glass 20-sided dice. A bit tricky to carry these around in your grandad's old Crown Royal bag, but otherwise, they make some pretty smashing (ahem) RPG accessories.
Now we need to cut 20 triangles out of our sheet of stained glass that match the template that we created. The easiest way to do that is to cut a stip of glass the same height as the triangles we cut in the jig. In the example pictures we used a strip that was 1.5" wide because our triangles ended up being 1.5" tall. Place the strip flush across the bottom of your cutting board and set your angle guide to 60 degrees. Follow your angle guide with your scorer so you end up with a 60 degree angle cut off the end of your glass strip. Depending on the kind of glass you bought you might simply need to flip it over to get the other side of the triangle, but the glass in the demo pictures is textured on the back, so we can only cut on the front, so we need to change our cutting guide to 60 degrees the other way. However you end up doing it, make sure that you are making your cuts and angle adjustments as precisely as you can, because if the triangles are not correctly shaped they will not make a good-looking d20.
Once you have 20 good pieces we can etch the numbers on them. Place each triangle in one of the holes of the cardboard template on the laser cutter's cutting surface. Now you can use the same file that we used to make the template but be sure to set your laser to etch only! We don't want to cut around the holes again!