I Think I'll Have Another Slice Of Pi

(CNN) -- The sound of meditation for Marc Umile is "3.14159265358979..." Whether in the shower, driving to work, or walking down the street, he'll mentally rattle off digits of pi to pass the time. He holds 10th place in the world for pi memorization -- he typed out 15,314 digits from memory in 2007.

Pi, the ratio of circumference to diameter of a circle, has captivated imaginations for thousands of years. Approximately 3.14, the number has its own holiday on March 14 -- 3-14, get it? -- which also happens to be Albert Einstein's birthday. You won't get off school for Pi Day, but you might be doing something special in school on Pi Day.

Mathematicians, teachers, museum directors, math students and other aficionados celebrate the number with pi recitations, pie-baking and pie-eating contests.

"There are many things that could not be built without implementing the constant pi," Umile said. "The great engineering marvels like the arch or suspension bridges we cross over, the tunnels spanning within mountains or even under the water that we drive through. ... Without it, everything would be incomplete or in danger of collapse."

That means, theoretically, that its digits will continue on indefinitely without ending in repetition -- in other words, the digits won't suddenly continue infinitely as 5s after 3 trillion digits (Pi's digits were calculated out to a record 2.7 trillion places in December by French computer scientist Fabrice Bellard).