I made this today for lunch with a friend (omni). It was really yummy! My Kroger happened to have purple potatoes for the first time this past week so I picked them up. They are really, really purple and very fun to use. After I pureed the soup it had a very dark purple color. When I added the lime juice, I suddenly had swirls of pink! The recipe didn't mention that it would happen, but it was pretty and cool. Everyone should try it just to see the (I'm supposing chemical) reaction.
Aaaand my ten-year-old said he is waiting to see if he gets to have Peruvian Purple Potato Poop.