The "Super Bowl Indicator" claims that when a team from the old NFL wins, stocks rise that year, and when an old-AFL team wins, they fall. It ran hot through the 1980s and 90s, hitting roughly 70-80% accuracy — then cooled to a coin flip once people started paying attention. It’s become a textbook example of spurious correlation, not an actual signal.

In 1954 the economist Armen Alchian worked out which fuel powered the U.S. hydrogen bomb — by watching the stock market. Noticing that Lithium Corp of America’s shares had jumped about 461% that year, he deduced the secret was lithium. The government ordered his paper destroyed.

In 1999 a chimpanzee named Raven picked stocks by throwing darts at a list of 133 internet companies. Her “MonkeyDex” portfolio returned 213% that year — ranking her the 22nd best-performing money manager in the U.S. and beating thousands of professional brokers, before the dot-com crash wiped the gains out.