This post has been updated.

We never need an excuse to eat pie, of the pizza or pastry variety, but here's one just in case: Pi Day.

For those of you who have tried to erase high-school geometry from your mind, a brief explainer: The Greek letter pi (this guy: π) represents a never-changing ratio of the circumference of a circle to its diameter. It is equal to 3.14 and then about a trillion other digits beyond its decimal point. Naturally, somebody at some point decided this would make a pretty cool "holiday" and ta-da, we get Pi Day on March 14; celebrants are especially excited this year because the next two digits after the commonly known "14" are "15." That's 3/14/15 if you need to see it all numerically. 

Anyway, let's get to what you really want to know: Who's running specials and events? (All are on Saturday unless otherwise noted.)

2941 pastry chef Caitlin Dysart will be offering slices of three house-made pies -- apple, triple-chocolate pecan and banana cream -- priced at $8 per slice on Friday and Saturday. Executive chef Bertrand Chemel is cooking two savory selections, a duck pithivier ($22, normally $28) and potato pie with black truffles ($18).

Baked and Wired in Georgetown will sell an array of pies and hand pies decorated with the pi symbol.

Bastille in Alexandria will serve individual chicken pot pies at brunch on Saturday and Sunday for $14.

Bayou Bakery in Arlington will sell $3.14 slices of Virginia peanut pie, lemon chess pie and apple crumble.

Blaze Pizza's locations in Bethesda, College Park and Laurel will offer any of its custom-made pies for $3.14 all day.

Bowie Baysox general admission tickets for home games April 16-20 will be available online from noon Friday to 11:59 p.m. Saturday for $3.14 (plus a $1.50 convenience fee).

Dangerously Delicious Pies on H Street will host two happy hours, from 9 to 11 a.m. and 7 to 10 p.m. During those windows, you can get a slice of sweet pie for $3.14 (there will be five choices).

Dolcezza's Dupont Circle and Logan Circle locations will be selling $5 slices of Whisked!'s chocolate bourbon pecan and pear cinnamon pies. Better still, make it a la mode with a scoop of gelato for $8.

Ice Cream Jubilee is giving away free cookie pie bites to the first 50 customers who make an ice cream purchase.

Joe's Seafood, Prime Steak & Stone Crab downtown will sell slices of its nine pies all day for $3.14 each. Flavors: Key lime, banana cream, chocolate marquise, Havana dream, peanut butter, coconut cream, apple, Boston cream and chocolate-dipped strawberry ice cream.

At Mellow Mushroom in Adams Morgan, a small cheese pizza is $3.14 until 3 p.m.

The National Cryptologic Museum in Fort Meade will offer a variety of family-friendly activities, including crafts and stories. Plus, you can figure out the diameter of your head using pi!

The Old Town Farmers Market in Alexandria is the place to go for samples from 7 a.m. to noon. Market-goers can pick up a "pi(e) passport" at the information desk in front of City Hall, which they can get stamped by various vendors offering tastes of pies, pie fillings and pie toppings. There will be whole pies from Maribeth's Bakery, Bread and Water and Kiwi Cuisine, jarred fruit fillings from Bigg Riggs Farm and Spring Valley Farm and Orchard and toppings from Misty Meadow Farm Creamery (ice cream) and Coulter Farms (cheddar cheese). Those who get their passport checked by all participating vendors will be entered into a raffle for market-branded merchandise.

Pi Pizzeria in Penn Quarter has a variety of specials all month and this week. With every purchase of a large pizza in March, you get a "gift" to use on your next visit, as well as a free large salad or appetizer. Wednesday, there's a seven-item, $5 dine-in menu, and you get a free Pi pint glass with the purchase of a full-price draft beer. On Thursday, if you dine-in and buy one large pizza, the second of equal or lesser value is $3.14, which you can pair with a $3.14 Schlafly Pi Common. Friday is an all-day happy hour, featuring discounted wings for $6. On Saturday, you can enter the pi memorization contest, where a $150 gift card is up for grabs. Also, anyone with a March 14 birthday who shows a government ID or birth certificate that day gets a free large pizza.

At Pizza Vinoteca in Ballston, a make-your-own pizza base is $3.14. Claim the offer here.

Pizzeria Paradiso in Georgetown will offer $3.14 brews at its beer bar from 9:26 p.m. until midnight. (If you've forgotten your pi, it begins 3.1415926.)

Radius Pizza in Mount Pleasant will sell pizza by the slice for $3.14 with the purchase of a beverage.

Room 11 will sell pies by the slice as well as whole pies made by its bakery, Paisley Fig, Friday through Sunday. You can also order pies for Saturday pickup between 9 a.m. and 7 p.m. (send orders by 5 p.m. Thursday to Nine-inch whole pies, with flavors such as banana cream, sweet potato and chocolate mud, run $27 to $30. Five-inch breakfast pies, in cheddar-chive-bacon and goat-cheese-caramelized-onion-kale flavors, are $5.

Teeny Pies is baking pies for pickup from 10 a.m. to 4 p.m. at Union Kitchen in Noma. All four-inch pies are $3.14 each, a set of four savory pies (all one flavor) is $31.41 and any nine-inch sweet pie and a copy of owner Teeny Lamothe's book, "Teeny's Tour of Pie," is $31.41. Order by Wednesday at

Whisked! pops-up from 1 to 4 p.m. at One Eight Distilling in Ivy City. Slices of pie and quiche will be for sale, in addition to six- and nine-inch pies (pre-ordering recommended). Options include apple, salted caramel apple and sea salt chocolate chess. The distillery will also be offering tours and tastings.

Area Whole Foods Markets will sell 9-inch apple pies for $9.99 (regularly $15.99).

Related items: