An inside joke (also known as an in joke or in-joke) is a joke whose humor is clear only to those people who are "inside" a social group or occupation. See also Mathematics of humor A joke is a short story or ironic depiction of a situation communicated with the intent of being humorous. Humour or humor (see spelling differences) is the tendency of particular cognitive experiences to provoke Laughter and provide Amusement They may be colloquially referred to as "You had to be there" moments. Inside jokes may exist within a small social clique, such as a group of high school friends, or they may extend to an entire profession (e. g. , inside jokes in the film industry).
An inside joke works to build community, at the expense of outsiders. Part of the power of an inside joke is that its audience knows that there are those who do not understand the joke.  Inside jokes are cryptic allusions to shared common ground that act as triggers. Only those who have shared the common ground provide an appropriate response. An inside joke can be a subtext, where someone will suddenly start laughing at something that is unspoken (usually to apologize for doing so, stating that what they were laughing at was an inside joke). Subtext is content of a book play musical work film video game or television series which is not announced explicitly by the characters (or author but is implicit or becomes 
In high school culture in the US, inside jokes are employed by all groups. The point of the joke is not humour, but recognition as a member of the group who was at the scene or informed of the circumstances. One is only a full member of a group if one "gets" the joke, even if the joke is based upon memories of events at which one was not present. 
A good example of an inside joke in recent filmmaking is the fact that despite his rampant anti-semitic opinions, Borat Sagdiyev speaks fluent Hebrew in his film Borat: Cultural Learnings of America for Make Benefit Glorious Nation of Kazakhstan. Borat Cultural Learnings of America for Make Benefit Glorious Nation of Kazakhstan is a 2006 This can be regarded as an inside joke, as it requires some knowledge of Hebrew (a language strongly associated with Judaism) to notice this.
In the computer industry, computer programmers hide "in jokes" within the code of software in the form of "easter eggs", which are hidden content that can be revealed by following a sequence of inputs. A virtual Easter egg is an intentional Hidden message or feature in an object such as a movie, Book
The Jargon File is a dictionary of programmers' slang, many of which are inner jokes or based on inner jokes. The Jargon File is a Glossary of hacker Slang. The original Jargon File was a collection of hacker slang from technical cultures such as the MIT AI