12th of never
n.— «The Biplane supposedly has a V-4, but the show bike is most likely a make-believe mockup. Looks to be straight out of a video game. When will either Suzuki be produced? Right after the 12th of Never.» —“Whees: Tokyo Motor Show: Two-Wheel Thunderdome” by Jerry Garrett New York Times Oct. 29, 2007. (source: Double-Tongued Dictionary)
Further reading
Astronauts returning from space say they experience what’s called the overview effect, a new understanding of the fragility of our planet and our need to reflect on what humans all share as a species. A book about the end of the universe...
Humpty-Bump Pull Top, Diamond Loop, Reverse Shark’s Tooth, Hammerhead, and Goldfish from the Top are all names of aerobatic maneuvers recorded in the Aresti System, designed by Spanish aviator Jose Luis de Aresti Aguirre as a means of...
It’s from an old folk song, variously known as “I Gave My Love a Cherry” or “The Riddle Song”: http://lyricsplayground.com/alpha/songs/numbers/12thofnever.shtml
Oops! Allow me to correct myself. Although the tune is quite old, the song “The Twelfth of Never” (containing, obviously, the phrase) is credited to Jerry Livingston and Paul Francis Webster, and was recorded by Johnny Mathis in 1957.