chalk
n.— «Chalk: Years ago—before computers, if you can imagine—bets were recorded on a large chalkboard. The favorites would get the most checks and thus the most chalk, making picking the chalk the term for picking the favorite. This, however, is nothing to be proud of. No one brags about picking the winner when the chalk comes home—which happens about a third of the time.» —“The lingo” Star-Ledger (New Jersey) Aug. 4, 2005. (source: Double-Tongued Dictionary)
Further reading
Sean in Oneonta, New York, says that when he was growing up in New Jersey, his family would pile in the car and set off on a surprise adventure, whether a short distance or long, and the kids would be told only that they were going on Buxtehude...
Amid court-ordered busing in the 1970s, a middle-school teacher tried to distract her nervous students on the first day of class with this strange assignment: find a monarch caterpillar. The result? A memorable lesson in the miracle of metamorphosis...