Shel,
You may be interested in knowing that carrots were never orange in nature. The orange carrot originated in the Netherlands in the 15th-16th century thanks to patriotic Dutch growers who bred the vegetable to grow in the colours of the House of Orange signifying the struggle for Dutch independence.
Mezz,
Purple carrots turn brown when cooked, so it's best to julienne or slice them for salads, etc.
If you don't find multi-colored carrots at your local grocery store, check around at
local farmer's markets. Ask the vendors so they know there is a demand.
You can also see if there is a
CSA in your area which is another great source for hard to find and unusual fresh produce.