Memorize this mnemonic and you can cite pi to twenty places. The number of letters in each word represents a digit of pi.
How I wish I could relocate pi,
“Eureka!” cried the great inventor,
Christmas pudding, Christmas pie,
Is the problem’s very center.
My brother and I used to challenge each other memorizing pi. I could only get up to 4626.
It got useful in later years when I had to come up with new passwords every 3 months on the work computers.