Saw this in one of my Grandma's old cookery books and had to give them a go. I thought they were brilliant but my boyfriend thought otherwise haha.
Par-boil the eggs for about 4 minutes in salty water.
Remove the eggs from the pan and carefully tap them all over with the back of a teaspoon. It doesn't matter if any small pieces of shell fall off, it will just add to the effect :D
Put a generous amount of food dye in each pan, and bring back to the boil, placing the eggs in.
remove after a few minutes, run under cold water and carefully take off the shell. Done!