A Reuben is an American grilled sandwich that consists of rye bread, corned beef, swiss cheese, russian dressing, and sauerkraut. It is a deli favorite, with considerable popularity on the East Coast of the United States. The invention of the sandwich is disputed (about who made it, not if it was invented or not).
Reuben is great. Eating it makes one want to speak in a New York accent, maybe while waving the sandwich around and letting some sauerkraut fly everywhere.
Reuben became an official snack on June 28th 2012.