Pi Day
March 14 · Level 6 · #1110 of 2238
Pi Day celebrates the constant that links a circle's circumference to its diameter. Its calendar trick is easy to spot: March 14, written as 3/14 in the United States, matches the first digits of π. It is an invitation to play with mathematics, whatever your confidence with numbers.
How it is celebrated: schools and science museums set circle puzzles, hold digit-reciting contests and serve pie. The food connection comes from the English pronunciation of pi and pie.
Physicist Larry Shaw organised the first celebration at San Francisco's Exploratorium in 1988. It included a circular procession and pie-eating.