Pi Day is a big pie day as well. (Pie via Twitter / @sweetnsavorypie)

Pi Day plays off the fact that March 14 – 3/14 – is a numerical pun on math’s best-known irrational number: pi, or 3.14. But there’s nothing irrational about punning pi, the ratio of a circle’s circumference to its diameter, with pastry as well.

The day has come to be known as a celebration of pie as well as pi (and, coincidentally, Albert Einstein’s birthday). In Seattle, pie tends to trump pi. Here are a few of Tuesday’s offerings:

  • In the Fremont neighborhood, the pastry shop known simply as Pie will celebrate the day by offering three mini-mini-pies for $3.14. Pie purchases are limited to six per customer. “It is literally our busiest day of the year,” says shop owner Jess Whitsitt.
  • The Downtown Seattle Association is one of the sponsors for a Pi Day pie-eating contest, set to start at noon at Occidental Square. Ten contestants will dig into coconut cream pies donated by Dahlia Bakery.
  • Big Mario’s Pizza in the Queen Anne neighborhood will be selling slices of pizza pie for $3.14 all day. Pagliacci Pizza is doubling down with a deal of two slices for $3.14 at its slice bars.
  • In the University District, the Academy for Precision Learning is selling Pi Day pies for $25 to the school’s families and friends.
  • A La Mode Pies’ stores in West Seattle and Phinney Ridge are running a contest to win a free pie-making class for 10 people, valued at $1,000. Meanwhile, Ballard’s Pie Bar is opening early to mark the day.
  • Lost Lake Cafe and Lounge on Capitol Hill is planning a pie-eating contest at 2 p.m., with $500 donated to the charity of the winners’ choice. The retro diner will also be serving up slices of goodness from A La Mode Pies for $3.14.
  • The ReachNow car-sharing service is offering up to one hour of driving to members in Seattle and Portland for $3.14.
  • The High Dive in Fremont has a 21-and-over Pi Day concert on the schedule for 8 p.m., with Circular Reasoning, Friction Pitch and Dead Nudes on the bill. Dead Nudes will preview their upcoming album, “They Eat Cake.” (What, no pie?)

On the scientific side of Pi Day, the Pierce College Science Dome in Lakewood is planning a Pi Day celebration that features a show called “Chaos and Order: A Mathematical Symphony.” Showings are scheduled at 5, 6 and 7 p.m. Be sure to get your tickets in advance: The 7 p.m. show is already sold out.

Pi Day got its start at the Exploratorium in San Francisco back in 1988, when physicist Larry Shaw organized a circular march and a bout of pie consumption to celebrate 3/14.

This year will mark the Exploratorium’s 30th annual Pi Day observance, and there’s even a Second Life virtual-world celebration. The procession gets under way at 1:59 p.m. (3/14, 1:59 … Get it?)

For a full rundown of Pi Day lore and happenings, check out PiDay.org or the #PiDay hashtag on Twitter. And if you want a second helping of irrational exuberance, or even a third serving, there’s plenty of time to get ready for Tau Day on June 28 (7/28) and Pi Approximation Day on July 22 (which is written in European-style date notation as 22/7, or roughly 3.1429).

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