The term "happening" was coined by Allan Kaprow in 1957 when he used the term in his famous essay, “Legacy of Jackson Pollock.” He defined the term as "events that, put simply, happen."  Kaprow was the leader of the Happening movement, and it followed him across the US as he taught at different universities (including Rutgers, Pratt, and UC San Diego). The term "Happening" quickly caught on and was soon used by other artists across the US and around the world. The term was also eventually appropriated by consumer culture.  While Happenings reached their prime during the late 1950's and 1960's, artists continued to employ this form of media throughout the rest of the 20th century.  Even today, Happenings still occur, whether in the form of brief events like Silent Discos and Flash Mobs, or longer festivals such as Burning Man.

Loose definition for "Happening": a new form of media art in which the audience plays a key role. Happenings are unique, one-time performances or events that are organized by an artist, but many aspects of the event are unscripted because they rely on audience participation. If the same happening was performed multiple times, it would have a different outcome each time because it depends on the actions and reactions of audience members. This form of art eliminates the traditional barrier between the performer/spectator and between the artist/artwork/viewer.  There are no rules, and therefore no room for failure. Happenings are free of the normal constraints that artists typically face (i.e. pleasing clients and receiving payment for their work); this is because Kaprow believed that the typical artist/patron relationship “is corrosive, neither patrons nor artists comprehend their role…and out of this hidden discomfort comes a stillborn art, tight or merely repetitive, and at worst, chic.” 

Related Adjectives:

unique, one-time, improvisational, participatory, performative, unpredictable, new, spontaneous, non-hierarchical, unstructured, interactive

Important artists and well-known Happenings:

Allan Kaprow - 18 Happenings in 6 Parts (1959), 

Red Grooms – The Burning Building (1959)

Yves Klein – The Immaterial Zone (1959)

Yoko Ono – Cut Piece (1964)

Robert Whitman, Jim Dine, Claes Oldenburg, Robert Delford Brown, Lucas Samaras, Robert Rauschenberg, Carolee Schneemann

Modern Happenings:   

Flash Mobs

Silent Discos

International Pillow Fight Day

Installations at Burning Man   

Sources:

http://en.wikipedia.org/wiki/Allan_Kaprow

http://en.wikipedia.org/wiki/Happening

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