Party

A party is a social gathering for celebration and recreation. While having some things in common with religious and seasonal festivals, the term "party" usually denotes a smaller gathering for a personal, rather than cultural, occasion even when the occasion is simply that of gaiety.

Parties provide numerous opportunities for social interaction of various kinds, depending on the participants and their understanding of the accepted behavior for a given occasion. As a result, they tend to reinforce cultural and/or counter-cultural standards, though sometimes this is simply by providing a semi-acceptable social context for violating some of those standards.
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And I just couldn't resist to place another Pink clip here.