Inkscape can be used to design parts to be cut out using laser cutters or CNC routers/plasma cutters. Here's a couple of introductory videos to get you started. The first one talks about the basic of designing and positioning a cut (but places the holes using guide lines rather than exact measurements). The second video talks about how to do more advanced layout. Remember, when you're ready to run it through a laser cutter, you need to export it as a PDF and open it in Adobe to do the cutting.
Risdon - 10.34.131.25
Dimmitt - 10.30.110.1
Nelsen - 10.32.100.40
Cardboard - Raster Power: 18.4; Raster Speed: 100; Res 500dpi; Burn top and middle layers, but not all the way through