Girl Scout cookies are cookies sold by Girl Scouts of the USA (GSUSA) as one of its major fundraisers for local Scout units. Members of the GSUSA have been selling cookies since 1917 to raise funds. Girls who participate can earn prizes for their efforts. There are also unit incentives if the unit as a whole does well. As of 2007, sales were estimated at about 200 million boxes per year.
The national Girl Scout organization reviews and approves all varieties proposed by the baking companies, but requires only three types: Thin Mints, Peanut Butter Sandwiches (ABC)/Do-Si-Dos (LBB) and Shortbreads (ABC)/Trefoils (LBB). The other kinds can be changed every year, though several popular favorites, such as Caramel DeLites (ABC)/Samoas (LBB) and Peanut Butter Patties (ABC)/Tagalongs (LBB), are consistently available.
Thin, mint-flavored chocolate wafers dipped in a chocolate coating
Vanilla cookies coated in caramel, sprinkled with toasted coconut and laced with chocolate stripes. The name "Samoas" is presumably an allusion to the tropical island of Samoa, derived from the tropical ingredients of coconut and cocoa.
Peanut Butter Patties
Crispy vanilla cookies layered with peanut butter and covered with a chocolate coating
Peanut Butter Sandwiches
Peanut butter filling sandwiched between crunchy oatmeal cookies
A traditional shortbread cookie made in the shape of the Girl Scout trefoil
Crescent shaped, lemon-wedge cookie with lemon chips and dusted in powdered sugar 
Dulce De Leche
Latin caramel cookies with caramel chips; earlier versions had a caramel topping, removed because of the high amount of trans fat
Thank U Berry Munch
Cranberries and white fudge chunks; discontinued in most markets for 2011, but still available in NYC suburbs
Shortbread cookie dipped in chocolate with a thank you message