Patbingsu is an amazing summertime treat that I first tried at Red Mango in Seoul (the chain doesn't offer it in the United States, to my knowledge). My Korean teacher says Shilla Bakery's is "the best."
This snack originally began as ice shavings and sweetened azuki beans (known as pat). It was sold by street vendors. In contemporary culture, it has become a very elaborate summer dessert, often topped with ice cream or frozen yogurt, sweetened condensed milk, fruit syrups, various fruits such asstrawberries, kiwifruit, and bananas, small pieces of tteok (rice cake), chewy jelly bits, and cereal flakes.
Bingsu are available in different flavors. Green tea and coffee are popular varieties.
Patbingsu is a summer specialty item found on the menus of most fast food restaurants in South Korea. KFC, McDonald's, Lotteria, and Burger King usually carry patbingsu on their menus from May to September. The ice cream/yogurt chains Pinkberry and Red Mango carry it year round.
Patbingsu is also a very popular dessert at cafés in New York's , Los Angeles', or Atlanta's Koreatown.