The United States
Politics and legislation
Voting Rights Act of 1965: Signed into law by President Lyndon B. Johnson, this act outlawed discriminatory voting practices based on race and was a major victory for the Civil Rights Movement.
Immigration and Naturalization Act of 1965: This act abolished the national-origins quota system, fundamentally reshaping the demographics of immigration to the United States.
Supreme Court: The U.S. Supreme Court's ruling in Griswold v. Connecticut (affirming the right to privacy regarding contraception).
Medicare: President Johnson signed Medicare into law as part of his "Great Society" initiatives, providing health insurance for the elderly.
Social and cultural events
Watts Riots: A six-day riot broke out in the Watts neighborhood of Los Angeles, leaving 34 dead and over 1,000 injured. The unrest was driven by anger over police practices and poverty.
Assassination of Malcolm X: The prominent civil rights and Black nationalist leader was assassinated on February 21.
Television: The animated special A Charlie Brown Christmas premiered on CBS.
Film: The Sound of Music, Darling, and Doctor Zhivago all debuted in cinemas. My Fair Lady won Best Picture at the Academy Awards.
Fashion: Mini skirts became a major fashion trend for women, and men began to grow their hair longer.
Science and technology
Mariner 4: The spacecraft became the first to fly by Mars and return images of the planet.
World's first space nuclear reactor: The U.S. launched the SNAP-10A, the world's first space-based nuclear power reactor.
The first space walk by an American: Edward White II in June. The Gemini 6 and 7 missions achieved the first orbital rendezvous of two spacecraft.
Inventions: The optical disk, which would later become the compact disk, was invented by James Russell. The touchscreen was invented by E. A. Johnson.
Communications: Early Bird, the first commercial communications satellite, was launched into orbit.
PDP-8: Digital Equipment introduced the PDP-8, the first commercially successful minicomputer to use integrated circuits.
Other notable events
Population: The world population was approximately 3.345 billion.
Vietnam War: The first U.S. combat troops were sent to Vietnam, and by the end of the year, American soldiers there numbered around 190,000.
Cost of living: A first-class stamp cost $0.05.
Toys: The skateboard and the super ball were extremely popular toys.