Maury Ginsberg was a spotlight operator at the famous Woodstock music festival in New York on Earth in 1969. He hitched a lift to the concert and noticed a disconnected cable that could have ruined the event. He was not aware that the man who drove him there was the member of the Q Continuum later known as Quinn.
Following the concert, Ginsberg went on to meet his future wife, a "groovy chick with the long red beads" that was in the backseat of Quinn's jeep. He then went on to become a successful orthodontist, settle in Scarsdale, and have four children.
Ginsberg was brought aboard the USS Voyager by Q in 2372 along with Sir Isaac Newton and Commander William T. Riker to provide evidence of Quinn's influence on history. He was returned shortly afterwards with no memory of this. (VOY: "Death Wish")