Prison inmates have a history of being gruesomely resourceful hackers. The toothbrush shiv comes immediately to mind. One such inmate in the UK wanted to offer tattoos to his fellow convicts so he came up with a tattoo gun using a PlayStation for parts. The crude setup involves a sharpened ballpoint pen and the use one of the motors from the optical drive to move it up and down. The inmate didn’t document his work for us but there are other examples of this method available. Even with modern hardware, ink seems a little 20th century when compared to laser tats.
[Thanks Memmy T]