National Tell a Joke Day takes place on August 16, 2014. A joke is something spoken, written, or done with humorous intention. Jokes may have many different forms, e.g., a single word or a gesture, a question-answer, or a whole short story. The word "joke" has a number of synonyms, including wisecrack, gag, prank, quip, jape and jest.
To achieve their end, jokes may employ irony, sarcasm, word play and other devices. Jokes may have a punch line, i.e. an ending to make it humorous. Jokes are typically for the entertainment of friends and onlookers. The desired response is generally laughter; when this does not happen the joke is said to have "fallen flat" or "bombed". However, jokes have other purposes and functions, common to comedy/humour/satire in general.
Jokes have been a part of human culture since at least 1900 BC. According to research conducted by Dr Paul McDonald of the University of Wolverhampton, a fart joke from ancient Sumer is currently believed to be the world's oldest known joke. Britain's oldest joke, meanwhile, is a 1,000-year-old double-entendre that can be found in the Codex Exoniensis. (With material from: Wikipedia)