This is a perfect desert for a summer gathering. Easily made in advance (and actually tastes better when very well chilled) this is a refreshing treat that's not too heavy after summer BBQ's. I use key limes when I can find them (Sprout's usually has them around August and September) but you can use regular limes just as easily. Be sure to serve this with plenty of fresh whipped cream. You will love it! *Although making this with middle schoolers was a bit of a gamble. As much as they say they like sour things (candies, etc.) some kids thought this pie was too sour for their liking. You may want to decrease the lime juice a bit if you are not into tang. I like tang so I like it just the way it's written.