Boing! Mango Juice, a little bit of fruity heaven is available at La Esquina in NYC, but it originally comes from Mexico. It's similar to the native drink Aqua de fruta, and therefore has no carbonation.
Other flavors are available, but I have yet to track them down. Most exciting are the tamarind, brand new peach, and guava, which I can only imagine are spectacular, if the delicious mango version is any indication.
Not everyone agrees with my very positive assessment of the beverage, but he got his by way of angry comments. The company, Pascual Boing, who manufactures the beverage, is just as good as the product, as wikipedia says it's “one of the few Mexican worker-owned companies that have national presence”.