Don't Sit on Potatoes on St Patrick's Day

To celebrate St. Patrick's Day I was going to do some research on diseases that make one's skin turn green. But in my quest I came across the following question on WikiAnswers: "Why does my skin turn green when I sit on potatoes?" While I sadly didn't know the answer, I am smart enough to know that we're missing important pieces to the puzzle. In the discussion section I posed these important questions:

1. Are you or is anyone you know Irish?
2. Were you wearing clothing and if so, was that clothing green or a combination of blue and yellow?
3. When you say "potatoes" do you really mean "parrots"?

I sure hope we can help this poor person, and happy St Patrick's Day everyone.