This is an old family recipe:
Peels removed from 2 or 3 grapefruits, in large sections
About 3 cups of sugar
Food coloring (optional)
Cover peel with cold water in a pot. Bring to a boil and cook until tender, but changing the water about 3 times.
Drain. With spoon, remove any remaining white from the peel. With scissors or sharp knife, cut the peel in thin strips. Meanwhile, boil 2 cups sugar with 1 cup water. (Some people add a drop or two of yellow coloring here for effect.) Add peel the peel and cook over low heat until peel beomes rather clear or "candied." Remove peel a few pieces at a time, but let the excess syrup to drain back into saucepan. Roll strips separately into the other cup of sugar until well coated. Set on a rack to cool.
And this is a bit more modern: http://www.virtualcities.com/ons/ca/g/cag95072.htm