After building an insulated cover for my 3D printer, I decided that I needed to put some lights inside. This allows me to see how the print job is progressing, both via the porthole, and via the interior webcam. Because green surplus neon tubes for computer cases are inexpensive and take 12 volts, I riced up the cover with two green neon tubes. The color complements the light teal of the foam insulation nicely, and gives my Garage Laboratory an evil green glow at night.