National S'mores Day takes place on August 10, 2018. A s'more (sometimes spelled smore) is a traditional nighttime campfire treat popular in the United States and Canada and consisting of a roasted marshmallow and a layer of chocolate sandwiched between two pieces of graham cracker.
Various confections containing graham cracker, chocolate, and marshmallow are often sold as some derivative of a s'more, but they are not necessarily heated or served in the same shape as the traditional s'more. The Hershey's S'mores bar is one example. Pop-Tarts also feature a s'mores variety.
S'more appears to be a contraction of the phrase "some more". While the origin of the dessert is credited to the entrepreneur Alec Barnum, the first recorded version of the recipe can be found in the publication Tramping and Trailing with the Girl Scouts of 1927. (With material from: Wikipedia)