Recently, Instructables found a new and shiny toy in the office -- Evil Mad Scientist's Egg-Bot. This is a really fun toy that allows you to create or import your design into Inkscape and print it on an egg.
As you can see from the pictures, you need to carefully place your egg within the machine and calibrate it properly using Egg-Bot's plugin for Inkscape to ensure that the pen always hits the egg as your design is being drawn. There is definitely an art to doing this well. These pictures are from my first attempts and tests, some of which turned out better than others.
Most of the images drawn on the eggs can be found online pretty easily as members of the community have shared their files.