"Yippies" were members of the Youth International Party, a counterculture movement mixing psychedelic hippies with political activists, that began in 1967. With a flair for theatrics and satirical pranks, the Yippies grabbed media attention in the U.S. protesting war and the criminalization of marijuana, and criticizing institutions of government and greed. Some of their most notable mischief included an attempt to levitate The Pentagon, nominating a Pig for President, throwing pies at politicians, and bringing Santa Claus to the House Un-American Activities Committee.

Pot, politics, music, performance and humor fueled the Yippies. Once referred to as "Groucho Marxists," they aimed to change the system and to provide a means of expression for everyone. According to one of the founders, Jerry Rubin, "We try to bring out the yippie in everybody."

Above all, Yippie! is shout of joy. As Abbie Hoffman, another founder of the Yippies, explained, "What does Yippie! mean? Energy -- fun -- fierceness -- exclamation point."