A love-in is a peaceful public gathering focused on meditation

Meditation

Meditation is any form of a family of practices in which practitioners train their minds or self-induce a mode of consciousness to realize some benefit....

, love, music, and/or use of psychedelic drugs. The term was coined by Los Angeles radio comedian Peter Bergman

Peter Bergman (comedian)

Peter Paul Bergman is an American writer and comedian, best known as a member of The Firesign Theatre. He plays Lt. Bradshaw in the Nick Danger series....

, who also hosted the first one in March or April 1967 (sources disagree) in Elysian Park.
It has been interpreted in different ways by different organizations, but is often connected to protest

Civil disobedience

Civil disobedience is the active, professed refusal to obey certain laws, demands, and commands of a government, or of an occupying international power. Civil disobedience is commonly, though not always, defined as being nonviolent resistance. It is one form of civil resistance...

ing local, social or environmental

Environmental movement

The environmental movement, a term that includes the conservation and green politics, is a diverse scientific, social, and political movement for addressing environmental issues....

 issues.
Such protests were held in opposition to the Vietnam War

Vietnam War

The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

.,