I would guess the greatest genius alive today is the 29 year old guy who built this . . . out of Legos . . .
http://www.youtube.com/watch?v=zX09WnGU6ZY
According to PC WORLD:
Hello World! One Lego enthusiast has made a working printer using spare Lego bricks, a felt-tip pen, a few mechanical parts, and a heap of ingenuity.
The homemade Lego printer, built by B3ta forum member "Squirrelfantasy," also features a number of hardworking Lego minifigures. See the printer--which uses the felt-tip pen in place of an ink cartridge--in action and watch the video after the jump.
The surprisingly accurate Lego Felt-Tip 110" Printer was all designed and coded from scratch, and was built with analog motors, sensors, a printer driver, and a wired USB interface.
Unlike mainstream printers, replacing the ink in this homemade effort is not a costly affair. When the printouts begin to fade simply buy a new felt tip pen and you're all set!