The Complete Guide to October's Obscure Holidays
October leans hard into autumn and the approach of Halloween — Carve a Pumpkin Day and Halloween itself close out the month, while National Mole Day (a chemistry pun on Avogadro's number) and Mad Hatter Day (a literal date hidden in a 19th-century illustration) show up in between.
This guide walks through all 62, day by day, with a bit of history or context for each one and a link to the full write-up — complete fun facts, ways to celebrate, and sourcing — on its own page.
Why does October have so many obscure holidays?
A genuine cluster of October's holidays are literary or pop-culture tributes tied to a specific text or date — Mad Hatter Day's price-tag pun, Mean Girls Day's exact movie quote, National Mole Day's chemistry constant, Dictionary Day marking Noah Webster's birthday. The back half of the month builds steadily toward Halloween, with pumpkin, candy corn, and mischief-adjacent holidays clustering in the final week.
How to use this guide
Holidays are grouped by date below. Each entry gets a short original write-up — not a repeat of the fact sheet — plus a link to the full holiday page if you want the deeper dive: complete fun facts, ways to celebrate, and sourcing.
October 1
âïļ International Coffee Day
Officially launched by the International Coffee Organization on October 1, 2015. Legend traces coffee's discovery to an Ethiopian goat herder named Kaldi, whose goats reportedly got energetic after eating coffee cherries. Full holiday page →
ðŠ National Homemade Cookies Day
The word “cookie” comes from the Dutch “koekje,” meaning “little cake.” Americans eat over 2 billion cookies a year. Full holiday page →
October 2
ð―ïļ National Fried Scallops Day
Scallops are unusual among bivalves for their ability to actually swim, rapidly clapping their shells together to propel themselves. Full holiday page →
ð National Name Your Car Day
A 2013 Esurance survey found that roughly 40% of American drivers had given their car a specific name. Full holiday page →
October 3
ðïļ Mean Girls Day
The date comes directly from the film's most quoted exchange — Cady recounting Aaron Samuels asking “What day is it?” and answering “It's October 3rd.” Lindsay Lohan originally auditioned for Regina George, the role that went to Rachel McAdams. Full holiday page →
ðŧ National Techies Day
Ada Lovelace is widely credited as the first computer programmer, for her 19th-century work on Charles Babbage's Analytical Engine. The word “bug” traces to Grace Hopper's team finding an actual moth causing a malfunction in 1947. Full holiday page →
October 4
âģïļ National Golf Lover's Day
The standard 18-hole course exists mostly by historical accident — St Andrews' Old Course set that number in 1764, and it just became the convention everyone followed. Full holiday page →
ðŪ National Taco Day
Americans eat an estimated 4.5 billion tacos a year. The word “taco” itself likely comes from 18th-century Mexican silver mines, originally referring to paper-wrapped gunpowder cartridges. Full holiday page →
October 5
ðĪ Do Something Nice Day
Traces to the early 2000s United States, with research backing up the core idea — performing kind acts genuinely boosts the giver's own happiness. Full holiday page →
ð National Apple Betty Day
Distinct from an apple crisp specifically because of its topping — buttered breadcrumbs or bread pieces, not an oat-based streusel. Full holiday page →
October 6
ðĐðŠðšðļ German-American Day
Marks the exact 1683 arrival of 13 German Quaker families in Philadelphia, who went on to found Germantown, Pennsylvania. It fell out of observance during World War I and wasn't officially revived until Ronald Reagan re-established it in 1983. Full holiday page →
ðĐ Mad Hatter Day
The date comes from a genuine visual detail — the “10/6” price tag on the Mad Hatter's hat in John Tenniel's original illustrations. Lewis Carroll never actually named the character “Mad Hatter” in the text. Full holiday page →
October 7
ð Bathtub Day
The earliest known personal bathtubs date to ancient Crete around 1700 BC, made of hardened pottery. Full holiday page →
ðĨĻðŦ National Chocolate Covered Pretzel Day
The pretzel component alone may date back to 610 AD in Europe, layered into a much more modern sweet-and-salty combination. Full holiday page →
October 8
ð American Touch Tag Day
Variations of tag have been documented across cultures for thousands of years. It's since evolved into an actual competitive sport, “World Chase Tag.” Full holiday page →
ðĨ Pierogi Day
The word “pierogi” is already plural in Polish — the singular form is “pieróg.” Full holiday page →
October 9
ðķ Leif Erikson Day
Marks Leif Erikson's landing in North America around 1000 CE, nearly 500 years before Columbus — though the October 9th date itself actually commemorates the 1825 arrival of the ship Restauration, marking the start of organized Norwegian immigration to the US. Full holiday page →
ð§ Moldy Cheese Day
The blue veins in Roquefort, Gorgonzola, and Stilton all come from Penicillium roqueforti, while Brie and Camembert's white rinds come from a related but distinct mold. Full holiday page →
October 10
ð° Angel Food Cake Day
Uniquely contains no butter, oil, or egg yolks at all — its entire structure comes from whipped egg whites. Full holiday page →
ð National Cake Decorating Day
Elaborate icing techniques saw a major boost in popularity during the Victorian era. Full holiday page →
October 11
ð National Running Backs Day
NBC's Sunday Night Football invented it on air in 2025, and on its October 4, 2026 broadcast it declared this year's for October 11, Ravens at Falcons. Full holiday page →
ð It's My Party Day
Directly inspired by Lesley Gore's 1963 hit song of the same name. Full holiday page →
ð Sausage Pizza Day
Sausage consistently ranks among the top five most popular pizza toppings worldwide. Full holiday page →
October 12
ð Cookbook Launch Day
The earliest known recipe collection, “Apicius,” comes from ancient Rome — arguably the first cookbook ever written. Full holiday page →
ðē Gumbo Day
The name likely comes from “ngombo,” a West African word for okra, reflecting the dish's African culinary roots. Full holiday page →
October 13
ðŦ National M&M Day
Inspired by Forrest Mars Sr.'s observation of Spanish Civil War soldiers eating chocolate pellets coated in a hard candy shell to prevent melting. The “M” stands for both Mars and Murrie. Full holiday page →
ð§ National Train Your Brain Day
The human brain weighs only about 3 pounds but consumes roughly 20% of the body's total oxygen and calories. Full holiday page →
October 14
ð§âðĶē Be Bald and Be Free Day
Historical and contemporary bald figures span from Julius Caesar to modern tech executives. Some studies have found bald men are occasionally perceived by others as more dominant or intelligent. Full holiday page →
ð° Dessert Day
The word “dessert” comes from the French “desservir,” meaning “to clear the table” — a reference to when the course is served, not what it contains. Full holiday page →
October 15
ð Mushroom Day
Mushrooms aren't plants at all — they belong to their own biological kingdom, Fungi, making them genetically closer to animals than to plants. Full holiday page →
ð National Grouch Day
Oscar the Grouch remains the most famous fictional grouch by a wide margin. Full holiday page →
October 16
ð Dictionary Day
Marks Noah Webster's birthday. His 1828 “An American Dictionary of the English Language” took 20 years to compile and included around 70,000 words, 12,000 of which had never appeared in any dictionary before. Full holiday page →
ð Feral Cat Day
Feral cats are genuinely distinct from strays — strays are lost or abandoned pets, while feral cats are born in the wild and typically avoid human contact entirely. Full holiday page →
October 17
ð National Pasta Day
There are more than 600 distinct documented pasta shapes worldwide. Noodle-like foods appear in Chinese cuisine as far back as 4,000 years, predating the Italian tradition. Full holiday page →
âĻ Wear Something Gaudy Day
The word “gaudy” actually traces to the Old French “gaudir,” meaning “to rejoice” or “to make merry.” Full holiday page →
October 18
ð§ National Chocolate Cupcake Day
The term “cup cake” first appeared in print in Amelia Simmons's 1796 cookbook “American Cookery.” Full holiday page →
ðŠ No Beard Day
Lands deliberately right before Movember, which encourages growing facial hair through November to raise money for men's health causes. Full holiday page →
October 19
ðĪ Evaluate Your Life Day
No widely documented origin, but the underlying premise mirrors standard self-improvement advice packaged as an annual prompt. Full holiday page →
ðĶ Seafood Bisque Day
The word “bisque” possibly traces to “bis cuites,” meaning “twice cooked,” referencing how the shells are prepared. Full holiday page →
October 20
ð Brandied Fruit Day
Before refrigeration, brandying fruit was a genuinely practical preservation method, not just a flavor choice. Full holiday page →
ðĶĨ International Sloth Day
Launched in 2010 by the AIUNAU Foundation. Sloths only climb down from trees to defecate roughly once a week, which is precisely when they're most vulnerable to predators. Full holiday page →
October 21
ð Count Your Buttons Day
The earliest known buttons, dating to around 2000 BCE in the Indus Valley Civilization, were purely ornamental, not functional fasteners. Full holiday page →
ð National Pumpkin Cheesecake Day
Cheesecake's documented history stretches back to ancient Greece, reportedly served at the Olympic Games. Full holiday page →
October 22
ð National Caps Lock Day
Reportedly created in 2000 by a programmer named Derek Arnold, amused by how often the key gets misused online. There's a second, separate Caps Lock Day on June 28th, tied to Billy Mays's birthday. Full holiday page →
ðĄ Smart is Cool Day
The average awake adult brain generates about 20 watts of electrical activity — enough to power a dim light bulb. Full holiday page →
October 23
âïļ National Mole Day
The date and time — 10/23, 6:02am to 6:02pm — are both pulled directly from the digits of Avogadro's number, 6.02 x 1023. Full holiday page →
ðĪ TV Talk Show Host Day
Marks Johnny Carson's birthday, who hosted NBC's “The Tonight Show” for 30 years and effectively set the format's template. Full holiday page →
October 24
ð National Bologna Day
The name traces to Bologna, Italy, the city that gave the world mortadella. The slang term “baloney,” meaning nonsense, is simply a phonetic spelling of the same word. Full holiday page →
ð National Food Day
Established in 1975 by the Center for Science in the Public Interest, built around five specific goals: real food, reducing diet-related disease, sustainable agriculture, food justice, and ending hunger. Full holiday page →
October 25
ð National Tight Ends Day
Started as a sideline joke between George Kittle and Jimmy Garoppolo in 2018, then made official by the NFL on the fourth Sunday of October. In 2024, tight ends set a single-day NFL record with 177 catches. Full holiday page →
ð National Greasy Foods Day
The specific combination of fat, sugar, and salt found in most greasy foods directly stimulates the brain's reward system. Full holiday page →
ð Sourest Day
A purely modern, whimsical holiday with no historical roots, built entirely around the shared experience of intensely tart candy and fruit. Full holiday page →
October 26
ðĨ§ Mincemeat Day
Genuinely used to contain actual chopped meat historically, which helped preserve the mixture before refrigeration existed. By the Victorian era, the meat had largely been replaced by suet. Full holiday page →
ð National Pumpkin Day
Pumpkins are technically a fruit, specifically a type of berry, since they carry seeds. Illinois alone grows more than 500 million pounds annually, the most of any US state. Full holiday page →
October 27
ðš American Beer Day
The US has more operating breweries than any other country in the world, with over 9,000 active as of recent counts. Full holiday page →
ðâ⎠National Black Cat Day
Black cats are considered good luck in several cultures, including Britain, Ireland, and Japan — directly opposite the superstition common in the US. Full holiday page →
October 28
ð§ļ Plush Animal Lover's Day
The teddy bear itself traces to Theodore Roosevelt's name, and Germany's Steiff company is widely credited with producing some of the first commercially made stuffed toys. Full holiday page →
ð Wild Foods Day
Foraging predates organized agriculture by hundreds of thousands of years. Several familiar cultivated vegetables, like carrots and cabbage, were selectively bred from wild foraged ancestors. Full holiday page →
October 29
ð§ Hermit Day
The word “hermit” comes from the Greek “eremites,” meaning “person of the desert,” originally describing early religious recluses. Full holiday page →
ðą National Cat Day
Founded in 2005 by Colleen Paige, the same advocate behind National Dog Day and National Puppy Day. Full holiday page →
October 30
ð Mischief Night
Known by different regional names depending on where you are — Devil's Night in Detroit, where it's historically been linked to a real spike in arson fires, or Cabbage Night in New England. Full holiday page →
ðŽ National Candy Corn Day
Invented in the late 1880s by George Renninger, originally marketed under the much less appealing name “Chicken Feed.” Roughly 9 billion pieces get produced every year. Full holiday page →
October 31
ð Carve a Pumpkin Day
The tradition actually started in Ireland with turnips and potatoes, not pumpkins. The name “jack-o'-lantern” comes from an old Irish folktale about a man named Stingy Jack, condemned to wander the earth with only a glowing coal inside a carved turnip. Full holiday page →
ð Halloween
Traces back to the ancient Celtic festival of Samhain, which marked the end of harvest season and the point when the boundary between the living and the dead was believed to thin. There's an actual clinical term for the fear of Halloween: samhainophobia. Full holiday page →
Frequently asked questions
How many obscure holidays are there in October?
62, spread across all 31 days.
What's the most unusual holiday in October?
National Mole Day (Oct 23) is a strong contender â chemistry enthusiasts observe it from 6:02am to 6:02pm specifically because those numbers match Avogadro's number, 6.02 x 10^23.
Are there a lot of Halloween-adjacent holidays in October?
Yes â Mischief Night, National Candy Corn Day, Carve a Pumpkin Day, and Halloween itself all land in the final two days of the month.
Where can I find the full history and fun facts for each holiday?
Every holiday name in this guide links to its own dedicated page with a longer write-up, sourced fun facts, and ideas for how to celebrate.
About this guide
This guide is part of the Obscure Holiday Calendar project — the same database that powers the iOS and Android apps and the individual holiday pages on this site. It exists to give a single, readable overview of an entire month at once, instead of requiring 62 separate page visits.