Nenana Ice Classic
A contest held every year in Alaska. Participants bet on when the ice in the Nenana River will melt.
In early March, a tripod is built on the ice and tied by a cable to a clock on a tower on the bank. When the ice breaks, the tripod falls over and the cable stops the clock; the person who guesses the date closest to the time the clock stops wins the jackpot ($\$300,\!000$ in 2016). Since its start in 1917 by bored railroad engineers waiting for the winter to end, a hundred years of data have been collected.
From the wikipedia article
The Nenana Ice Classic is a non-profit charitable gaming organization. As such, the proceeds benefit many volunteer and non-profit organizations. […] In 1917, railroad engineers bet $\$801$ on when the ice would break. In 2009 the 93rd annual prize money was $\$283,\!723$. In 2014 the jackpot was a record $\$363,\!627$. Since the Classic’s beginning in 1906 over 10 million dollars in prize money has been given away.
- Official website: https://www.nenanaakiceclassic.com
- Spreadsheet data. Date accessed: 15 January 2026.
- Sample problem statements from Deborah Hughes-Hallett