The Complete Guide to April's Obscure Holidays
April swings from April Fools' Day pranks straight into a month full of genuinely offbeat food, science, and pop-culture holidays — Bicycle Day marks the discovery of LSD, Talk Like Shakespeare Day lands on his actual birth and death date, and there's an entire holiday dedicated to lima beans getting a fair shake.
This guide walks through all 60, 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 April have so many obscure holidays?
A noticeable cluster of April's holidays are built on real, dated events rather than invented themes — Samuel Morse's birthday, Albert Hofmann's 1943 bicycle ride, the Cullen-Harrison Act ending Prohibition's beer ban, and Shakespeare's birth and death both landing on the same date. Food holidays run especially dense this month too, with pretzels, jelly beans, garlic, grilled cheese, and prime rib all getting their own day within a few weeks of each other.
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.
April 1
๐ April Fools' Day
One popular theory traces the tradition to the 16th-century shift to the Gregorian calendar, when people still celebrating New Year's in late March/early April got mocked as “fools” for not updating. The prank has its own regional flavor in France, Italy, and French Canada, where it's a “poisson d'avril” — an April fish taped to someone's back. Full holiday page →
๐ช One Cent Day
The U.S. Mint has repeatedly reported that producing a single penny costs more than one cent, which makes this holiday's entire premise a little bittersweet. Pennies minted after 1982 are actually 97.5% zinc, just plated with a thin shell of copper. Full holiday page →
April 2
๐พ National Ferret Day
The word “ferret” comes from the Latin furittus, meaning “little thief” — a fairly accurate name given their habit of stashing random objects. When excited, they perform something actually called a “weasel war dance,” an energetic bouncing routine. Full holiday page →
๐ฅช National Peanut Butter and Jelly Day
The earliest known written PB&J recipe appeared in 1901, in the Boston Cooking-School Magazine — decades before it became a lunchbox staple. Its real popularity boost came during World War II, when both ingredients were cheap, nutritious, and easy to ship as rations. Full holiday page →
April 3
๐ Find a Rainbow Day
A rainbow is only visible under one specific condition: the sun has to be behind you and water droplets in front of you. What looks like an arc from the ground is actually a full circle — the horizon just blocks the bottom half. Full holiday page →
๐ World Party Day
Traces to a 1996 science fiction novel, “Skipping Towards Gomorrah,” which floated the idea that if the entire planet partied simultaneously, nobody would be free to start a conflict. It's stayed purely grassroots ever since, with zero official government backing anywhere. Full holiday page →
April 4
๐คฅ Tell a Lie Day
Functions as a kind of unofficial sequel to April Fools' — a second chance at harmless deception for anyone who missed the 1st. The entire spirit is storytelling and exaggeration, not anything meant to actually mislead someone. Full holiday page →
๐ World Rat Day
Founded in 2002 by rat enthusiasts specifically to correct the animal's reputation — pet rats are genuinely fastidious, spending hours a day grooming themselves and each other. They're also trainable enough to learn their own names and navigate mazes. Full holiday page →
April 5
๐ Deep Dish Pizza Day
Credited to Pizzeria Uno in Chicago in 1943, and the assembly order is inverted from a normal pizza on purpose — cheese goes directly on the crust first, then toppings, with the chunky tomato sauce layered on top last specifically to keep the cheese from burning. Full holiday page →
๐ฏ Go for Broke Day
The phrase became famous as the motto of the 442nd Regimental Combat Team, a Japanese-American unit that became one of the most decorated in U.S. military history during World War II — a much heavier history than the holiday's casual “take a risk” framing usually acknowledges. Full holiday page →
April 6
๐บ New Beer's Eve
Marks the eve of the Cullen-Harrison Act taking effect in 1933, which let Americans legally buy beer again for the first time in over a decade — Roosevelt signed it with the famously understated line, “I think this would be a good time for a beer.” Full holiday page →
๐ด๓ ง๓ ข๓ ณ๓ ฃ๓ ด๓ ฟ Tartan Day
Marks the 1320 signing of the Declaration of Arbroath, a letter asserting Scotland's independence to Pope John XXII — a genuinely old document to anchor a holiday that's actually quite recent. It started in Canada in the 1980s, and the U.S. only formally recognized it via a 1998 Senate resolution. Full holiday page →
April 7
๐บ National Beer Day
Marks the actual effective date of the Cullen-Harrison Act, the day after New Beer's Eve — breweries reportedly sold 1.5 million barrels on this single day in 1933. The modern celebration is much younger, started as a social media push in 2007 by two guys in Richmond, Virginia. Full holiday page →
๐๏ธ No Housework Day
No formal origin, no founder — just a shared cultural agreement that skipping chores for one day is worth its own holiday. The suggested activities are refreshingly unambitious: order takeout, read, or just do nothing. Full holiday page →
April 8
๐ฆ Draw a Picture of a Bird Day
Bird illustration has real scientific weight behind it — John James Audubon's “The Birds of America” (1827–1838) remains a foundational ornithological reference, not just decorative art. Full holiday page →
๐ฆ Zoo Lovers Day
The world's oldest continuously operating zoo, Vienna's Tiergarten Schönbrunn, has been open since 1752. Modern accredited zoos run actual breeding programs for endangered species and sometimes reintroduce animals to the wild. Full holiday page →
April 9
๐ท๏ธ Name Yourself Day
Purely symbolic — unlike a legal name change, this is entirely about imagining a different identity for a day, not making it official. Explicitly framed as a “wacky holiday” rather than anything formally recognized. Full holiday page →
๐ฆ Unicorn Day
The unicorn has been Scotland's official national animal since the 15th century, which is a strange bit of trivia for a mythical creature. The earliest known depiction of something unicorn-like dates back to the Indus Valley Civilization, roughly 2500–1900 BC. Full holiday page →
April 10
๐ฅ National Cinnamon Crescent Day
The word “croissant” is literally French for “crescent,” a direct reference to the shape rather than a brand name. Cinnamon itself is one of the oldest spices in continuous use, appearing in both culinary and medicinal contexts for thousands of years. Full holiday page →
๐ซ National Siblings Day
Founded in 1995 by Claudia Evart, who chose the date specifically in memory of her late sister, Lisette — a genuinely personal origin story rather than an invented marketing holiday. Multiple U.S. presidents have issued proclamations recognizing it since. Full holiday page →
April 11
๐ค Barbershop Quartet Day
Marks the 1938 founding of what's now the Barbershop Harmony Society in Tulsa, Oklahoma. The style's signature effect, the “ringing chord,” comes from four voices tuning pure intervals so precisely that the overtones create the illusion of extra voices singing along. Full holiday page →
๐พ National Pet Day
Founded in 2006 by the same person behind National Puppy Day and National Dog Day, Colleen Paige — a recurring name across this calendar's pet-holiday cluster. Adoption promotion is baked into the mission as much as the general appreciation angle. Full holiday page →
April 12
๐ฌ๏ธ Big Wind Day
Marks the 1934 measurement of a 231 mph wind gust atop Mount Washington, New Hampshire — the highest surface wind speed ever directly recorded by an instrument at the time, and it held that record for 62 years. The summit still averages 110 days a year with hurricane-force winds. Full holiday page →
๐ง National Grilled Cheese Sandwich Day
Traces back further than people expect — early versions existed in ancient Rome — but the modern sandwich only took off in the 1920s, once sliced bread and cheap processed cheese became widely available. During the Great Depression it became a staple specifically because it was cheap and fast. Full holiday page →
April 13
๐ฅช National Make Lunch Count Day
Actively promoted by the American Institute for Cancer Research, built around a simple, research-backed idea: stepping away from your desk to eat measurably reduces stress and improves digestion. Full holiday page →
๐ก National Scrabble Day
Marks inventor Alfred Butts' birthday. He determined the game's letter values and frequencies by literally counting letters on the front page of The New York Times. It was originally called “Criss-Crosswords” before the Scrabble rebrand. Full holiday page →
April 14
๐ฌ Dolphin Day
Dolphins have the second-highest brain-to-body weight ratio of any mammal, behind only humans, and they hunt cooperatively within complex social groups called pods. Their navigation system, echolocation, works on the same basic principle as sonar. Full holiday page →
โ๏ธ Look Up at the Sky Day
The sky's blue color comes down to Rayleigh scattering — shorter blue wavelengths scatter more efficiently through the atmosphere than other colors. There are exactly 88 officially recognized constellations used to map the entire night sky. Full holiday page →
April 15
๐งบ National Laundry Day
Before washing machines, laundry meant beating clothes against rocks or scrubbing them on a washboard in a river. Dry cleaning was discovered by accident in the mid-19th century, when a French dye-works owner's maid spilled lamp oil on a tablecloth and it came out cleaner than the fabric around it. Full holiday page →
โ๏ธ Rubber Eraser Day
Before rubber erasers existed, people used wads of moist bread to lift pencil marks off paper. The material's name comes from chemist Joseph Priestley in 1770, who noticed it could literally “rub out” graphite. Full holiday page →
April 16
๐ Day of the Mushroom
Only about 140,000 of an estimated 2.2 to 3.8 million fungal species have ever been formally described. One single fungus, a honey mushroom in Oregon, spreads across thousands of acres underground and ranks among the largest living organisms on Earth. Full holiday page →
๐ด Wear Your Pajamas to Work Day
Lands the day after the U.S. federal tax deadline, which is probably not a coincidence — a low-effort way to soften the stress of April 15th. Remote work has made the whole premise less of a novelty and more of an actual daily reality for a lot of people. Full holiday page →
April 17
๐ฌ Blah Blah Blah Day
Traces to early-2000s internet culture, born as a reaction to information overload well before “content fatigue” became a mainstream complaint. Some participants mark it by attempting a full day of “blah-free” conversation. Full holiday page →
๐ Haiku Poetry Day
The form evolved from hokku, the opening stanza of a longer linked-verse sequence called renga, before it split off as its own independent poem. Matsuo Bashō, its most celebrated master, wrote in 17th-century Japan. Full holiday page →
April 18
๐ฆ National Animal Crackers Day
Originally branded “Barnum's Animals Crackers” in 1902, a direct nod to the Barnum and Bailey Circus. In 2018, Nabisco redesigned the box art in collaboration with PETA, depicting the animals roaming free on a savanna instead of caged. Full holiday page →
โ National High-Five Day
The earliest documented high-five is credited to Dodgers players Dusty Baker and Glenn Burke, during a game on October 2, 1977. The holiday itself is much younger, started by University of Virginia students in 2002. Full holiday page →
April 19
๐ฒ Bicycle Day
Marks Swiss chemist Albert Hofmann's 1943 bike ride home after accidentally discovering LSD's psychoactive effects — he'd synthesized the compound five years earlier but only realized what it did after a self-experiment gone further than planned. Full holiday page →
๐ง National Garlic Day
Ancient Egyptians reportedly fed garlic to the laborers building the pyramids, believing it provided strength and stamina for the work. China alone now grows more than 75% of the world's garlic supply. Full holiday page →
April 20
๐ซ Lima Bean Respect Day
Named for Lima, Peru, where the bean was first cultivated roughly 8,000 years ago — a much older food than its reputation as a disliked side dish would suggest. In the American South, larger, creamier varieties go by an entirely different name: butterbeans. Full holiday page →
๐ฏ Look Alike Day
Entirely informal, with no founder or proclamation behind it — just a shared excuse to hunt for celebrity doppelgängers or notice who resembles whom. Full holiday page →
April 21
๐ถ Bulldogs Are Beautiful Day
The breed's original purpose was bull-baiting, a brutal blood sport — a jarring contrast to the gentle, loyal temperament modern Bulldogs are known for today. Their short-nosed structure makes them poor swimmers and prone to breathing issues. Full holiday page →
๐ต National Tea Day
The UK's dedicated tea holiday, and worth remembering that all “true” teas — black, green, white, oolong, pu-erh — come from a single plant, Camellia sinensis. The afternoon tea tradition only dates to the mid-1800s. Full holiday page →
April 22
๐ฌ National Jelly Bean Day
The earliest known jelly bean advertisement dates to 1861, encouraging people to mail them to Union soldiers during the Civil War. Ronald Reagan was famously fond of them, reportedly keeping jars in the Oval Office. Full holiday page →
๐งบ National Picnic Day
The word traces to the 17th-century French pique-nique, describing a potluck-style social gathering. Picnics became genuinely popular in Europe only after the French Revolution, when royal parks — previously off-limits — opened to the public. Full holiday page →
April 23
๐น Lover's Day
Marks Catalonia's Sant Jordi's Day, where the tradition runs opposite to most romantic holidays: men give women roses, women give men books, and city streets turn into open-air markets for both. Full holiday page →
๐ Talk Like Shakespeare Day
April 23rd is traditionally recognized as both Shakespeare's birth date (1564) and death date (1616), a rare symmetry that makes the date choice easy. He's credited with coining or popularizing hundreds of words still in everyday use, including “eyeball” and “swagger.” Full holiday page →
April 24
๐ญ Pig in a Blanket Day
The earliest known mainstream American recipe appeared in Betty Crocker's Cooking for Kids in 1957. In the UK, the same name refers to something entirely different: sausages wrapped in bacon, not pastry. Full holiday page →
๐ฅ Sauvignon Blanc Day
The name literally translates to “wild white,” referencing its origins as an indigenous vine in southwestern France. It's also one of the two parent grapes of Cabernet Sauvignon. Full holiday page →
April 25
๐ National Zucchini Bread Day
Zucchini is botanically a fruit, not a vegetable, since it develops from the plant's flower and carries seeds — the same technicality that applies to tomatoes. Its popularity as a quick bread surged specifically in the 1970s. Full holiday page →
๐ง World Penguin Day
Timed to coincide with the annual northward migration of Adélie penguins in Antarctica, not chosen arbitrarily. All 18 penguin species live exclusively in the Southern Hemisphere. Full holiday page →
April 26
๐ Get Organized Day
The average person reportedly spends an entire year of their life searching for lost items. Benjamin Franklin, with his famously rigid daily schedule, gets cited constantly as an early poster child for the concept. Full holiday page →
๐ฅจ National Pretzel Day
The pretzel's twisted shape is often traced to European monks around 610 AD, meant to resemble arms crossed in prayer. Pennsylvania alone produces roughly 80% of all pretzels made in the United States. Full holiday page →
April 27
๐ก Morse Code Day
Marks Samuel Morse's birthday. The very first message sent via his telegraph, in 1844, was “What hath God wrought?” — a deliberately dramatic opening line for what became a communication standard used for over a century afterward. Full holiday page →
๐ฅฉ National Prime Rib Day
Cut from the primal rib section, typically ribs six through twelve, and traditionally cooked standing upright on its own bones, which double as a natural roasting rack. Full holiday page →
April 28
๐ข National Cubicle Day
The modern cubicle traces to a specific 1968 design, Robert Propst's “Action Office II” for Herman Miller — originally meant to offer more privacy and flexibility than the open-plan offices it replaced. Full holiday page →
๐ฆธ Superhero Day
Deliberately broad in scope — covering both fictional comic-book characters and real people who act with courage or selflessness, rather than limiting the idea to capes and costumes. Full holiday page →
April 29
๐ค Shrimp Scampi Day
“Scampi” originally refers to langoustines, small lobster-like crustaceans — Italian-American cooks adapted the garlic-butter-wine preparation to shrimp when langoustines weren't available. It's genuinely one of the fastest dishes to make, typically done in under 20 minutes. Full holiday page →
๐ Zipper Day
The zipper's precursor, a “Clasp Locker,” was patented in 1893, but the reliable version people actually use dates to Gideon Sundback's 1917 “Separable Fastener.” The name wasn't coined until 1923, by B.F. Goodrich. Full holiday page →
April 30
๐ง Bubble Tea Day
Originated in 1980s Taiwan, with two competing tea houses both credited with inventing it. “Boba” technically refers just to the tapioca pearls, though it's now used interchangeably with “bubble tea” worldwide. Full holiday page →
๐ช National Oatmeal Cookie Day
The earliest known recipe appeared in Fannie Merritt Farmer's 1896 Boston Cooking-School Cook Book. Quaker Oats did more than anyone to popularize it after that, printing recipes directly on their oat containers in the early 20th century. Full holiday page →
Frequently asked questions
How many obscure holidays are there in April?
60, spread across all 30 days.
What's the most unusual scientific holiday in April?
Bicycle Day (Apr 19), marking Albert Hofmann's 1943 bike ride home after the first intentional LSD trip โ a genuinely pivotal, if unconventional, date in the history of psychedelic research.
Are there a lot of food holidays in April?
Yes โ National Pretzel Day, National Grilled Cheese Sandwich Day, National Prime Rib Day, National Garlic Day, Deep Dish Pizza Day, and several more make up close to a third 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 60 separate page visits.