# Save the Date: National Stuff That Was Popular When You Were a Kid Day

Are you planning to celebrate National Stuff That Was Popular When You Were a Kid Day on Monday?

I understand if you're not, as it's a new holiday that we're inventing. Reader Virginia Scott suggested it in our Make Up Your Own Holiday contest. (Monday is also National Make Up Your Own Holiday Day.)

We'll be celebrating here throughout that day. I've asked a dozen mental_floss regulars of various ages with various interests to put together a quiz about something they loved growing up. If you plan to celebrate, let us know how. Get in on the ground floor while traditions are being established.

If you can't wait that long, here are some quizzes from the archives that fit right in:

iStock
Happy Phi Day: The Last Day to Match the Golden Ratio for a Century
iStock

Math whizzes may have noticed something particularly pleasing about today's date. According to Bloomberg, June 1, 2018 (formatted as 1/6/18 in many parts of the world) is Phi Day, a date that matches the first four digits of the golden ratio.

Represented by the 21st letter of the Greek alphabet, the golden ratio, which comes out to roughly 1.618 when rounded, is the number you get when you divide a line into two parts so that the longer part divided by the smaller part is the same as the total length divided by the longer part (or simplified: When the smaller is to the larger as the larger is to the whole).

Non-mathematicians might know it better as the number that appears constantly in nature, art, and architecture. The Pyramids at Giza, Leonardo da Vinci's "Vitruvian Man," nautilus shells, sunflower seed heads, and spiral galaxies all feature the golden ratio.

The golden ratio is also closely related to the famous Fibonacci sequence. In this series of numbers beginning with zero or one, each subsequent number equals the sum of the previous two (i.e., 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, etc.). The ratio of any two successive numbers in this sequence comes very close to the golden ratio. Shapes made with Fibonacci dimensions are considered pleasing to the eye, which is why they so often appear in art, either unintentionally or by design.

Unlike other math holidays such as Pi Day, Phi Day only comes once a century. You can celebrate the once-in-a-lifetime occasion by taking a walk outside and seeing how many examples of the golden ratio you can spot in your neighborhood.

[h/t Bloomberg]

iStock
It's National Pizza Day! Here Are the Chains Offering the Best Deals
iStock

Pizza comes about as close to perfection as food can get. Now, in honor of National Pizza Day—which is today, February 9—some fine purveyors of the cheesy delicacy have made it even more irresistible. If you’re looking for a place to celebrate this glorious holiday, these are the restaurants giving away their pizza at discounted costs or at no cost at all.

At Round Table Pizza, a pizza chain in the western U.S., getting a free cheese or pepperoni personal pizza all to yourself is easy. Just order a Pepsi beverage from one of their stores between 2 p.m. and 5 p.m on Friday. Pilot Flying J, a national truck stop chain that sells pizza, is giving away slices now through February 10 to any customer who downloads their myPilot app and redeems the digital coupon. Downloading the app from Blaze Fast Fire'd Pizza will get you a buy-one-get-one-free pizza deal all the way up until February 13 when you use their digital code. Chuck E. Cheese's is also going the buy-one-get-one route: Buy any large pizza there and get a free large thin-crust pepperoni pizza at no additional charge.

While nothing beats free pizza, discounted pizza is also abundant on National Pizza Day. Pizza Hut, the largest pizza chain in the U.S., is reducing all menu-priced pizzas by 30 percent for Hut Rewards members. Their biggest competitor, Domino’s, is offering a special that lets customers buy any two items from a list of goodies like wings, pizza, and cheesy bread for \$5.99 total. At Papa John’s, they're celebrating Pizza Day for an entire month: Through March 5, you can order their Dual Layer Pepperoni Pizza for \$12.

And if you’re a pizza lover who prefers your local by-the-slice joint to national chains, you still have options. Slice, a delivery app that connects customers to local pizzerias, will take \$5 off orders of \$10 or more when you enter the code “PIZZADAY.” If you can’t find your favorite spot that way, you can always give them a call and ask if they’re doing anything special to mark the big day.

[h/t Today]

### SECTIONS

arrow
LIVE SMARTER
arrow
LIVE SMARTER
More from mental floss studios