1. Darwin Day (Feb. 12)
    The birthday of Charles Darwin is also a celebration of his life, works, scientific method — and for eating primordial soup. Reenactments of the Scopes Trial are strictly optional.
  2. Pi Day (Mar. 14)
    The 14th day of the third month is unofficially dedicated the irrational mathematical constant used to calculate many key geometric values. And, so long as we’re punning on 3.14159…, the (over)consumption of pie is often encouraged.
  3. Tolkien Reading Day (Mar. 25)
    Commemorating the (fictional) anniversary of the Fall of Sauron, Tolkien Reading Day is one of two major geek holidays dedicated to partaking of the Middle Earth imaginings of one J. R. R. Tolkien. And no, watching the movie and TV adaptations doesn’t count. Crack a book, you orc.
  4. Yuri’s Night (Apr. 12)
    On the anniversary of the first human spaceflight, undertaken by one Yuri Gagarin, rocket geeks the world over attend at least one of a series of parties thrown to celebrate, commemorate, and drive interest in the exploration of outer space. Explosives and/or vodka are usually involved.
  5. Pixel-Stained Technopeasant Day (Apr. 23)
    A snarky nouveau holiday devoted to the encouragement of posting fiction (particularly science fiction) online for free. A favorite day of copyleftists and those who simply believe that online and digital publishing should be gleefully embraced. To be enjoyed with some digital genre fiction you didn’t steal, but didn’t pay for. (*COUGH*shameless plug*COUGH*)
  6. Free Comic Book Day (First Saturday in May)
    In case you didn’t know, you can walk into most any comic book shop on the first Saturday in May and find a stack of special edition comics, provided by every major comics publisher, available absolutely free. The celebratory rites are pretty self-explanatory.
  7. Star Wars Day (May 4)
    “May the 4th be with you” is the pun-ful justification for invoking the hallowed works of Jedi fiction we all know and love, usually in costume, and definitely with toy lightsabers and a surfeit of Yoda quotes. For extra points, remark on how this is all Margaret Thatcher’s fault. (No, really.)
  8. Towel Day/Geek Pride Day (May 25)
    Two weeks after his death on May 11, 2001, fans of Douglas Adams gathered to celebrate his life and works, most especially the one that taught us those twin axioms: “don’t panic” and “always know where your towel is.” The date, by sheer intentional coincidence, was also the anniversary of the original release of Star Wars in 1977. This confluence led to pretty much everyone letting their geek flag fly, regardless of which franchise you support, though carrying 42 lightsabers and answering to the name Darth Zaphod might be going too far. (Not really.)
  9. Tau Day (Jun. 28)
    Star Wars vs. Star Trek? Buffy vs. Twilight? You ain’t seen a geek feud until you’ve waded into the Pi vs. Tau debate over which is the more worthy scientific shorthand for the ratio of a circle’s circumference to its diameter. Celebrations include educating others on why pi is wrong, and why pie is still right. (Mostly by eating the latter.)
  10. SysAdmin Day (Jul. 27)
    The website you’re reading this post on? Made possible by sysadmins. The networked laserjet your boss’s secretary prints his emails on? Also made possible by a sysadmin. At least one of you should give the guy a Starbucks gift card or some discount ThinkGeek swag, and it ain’t gonna be the boss or the secretary. Man up, end-user.
  11. Programmer’s Day (Sep. 12 or 13)
    On the 256th day of the year (AKA the hexidecimal 100 day), the code monkeys that make the modern world possible finally get a quasi-official holiday (except in Russia, where it’s an actual holiday). The one day of the year where hacking is always white hat, and not knowing what “reindeer flotilla” means is uncool.
  12. Talk Like A Pirate Day (Sep. 19)
    All those annoying seagoing catchphrases that Johnny Depp fanboys run into the ground become hip again on this day, when the completely a-historical conception of pirate-speak be the order of the day, matey. And those that be speaking ag’in such finery shall walk the plank. Savvy?
  13. Hobbit Day (Sep. 22)
    The other Tolkien holiday, coincidental with the birthday of Bilbo and Frodo Baggins. This is the one where it’s OK to watch the movies, though the Rankin-Bass animated version is preferred.
  14. Ada Lovelace Day (Oct. 16)
    Named in honor of the pioneering lady logician who developed most of the core concepts behind programmable logic (as in computer software), Ada Lovelace Day is an occasion for celebrating women in science. Geek girls, this one’s for you.
  15. Mole Day (Oct. 23)
    The one geek holiday you probably learned about in school, it’s technically named for the role of Avogadro’s Number in chemistry, but is more generally dedicated to the celebration of the science that gave us medicine, plastics, and — above all — high explosives. Recommended celebrations include model rockets and MythBusters marathons.
  16. Back to the Future Day (Nov. 5)
    Nov. 5, 1955, the day Dr. Emmett Brown conceived of the flux capacitor and thus invented time travel. Technically, 1980s retro-future fashions and Huey Lewis music parties are acceptable celebrations, but we’ve only got three years left to invent flying cars, hoverboards and weather control — and for network fax machines to overtake the Internet — so let’s get on that.
  17. Computer Security Day (Nov. 30)
    If only for this one day, change your password without being asked. And update your AV software. Please.
  18. Day of the Ninja (Dec. 5)
    The ninja equivalent of Talk Like A Pirate Day, except ninjas are too stealthy to talk. If you can’t wear a ninja mask, gi and tabi boots to work, then just disappear for the day to watch chop-socky films and play Ninja Burger. Your clan’s honor demands it.
  19. Festivus (Dec. 23)
    The next best (non-commercial) thing to Christmas, enjoy your meatloaf, airing of grievances, and feats of strength as you gather ’round the Festivus pole and collect donations for The Human Fund. Just don’t forget the true meaning of Festivus.
  20. Grav-Mass (Dec. 25)
    Sir Isaac Newton, inventor of both calculus and physics and thus the ur-geek of all geeks, was born on Christmas Day. As such, the more science-oriented among us may decorate our seasonal trees with heavy but poorly secured apples and let gravity take its course. Sing the one and only Grav-Mass carol while you wait. Extra points for doing this in a vacuum and including feathers and cannonballs in your decor, just to prove a point. Appletinis and derivative equations round out the festivities.

Got a holiday you think deserves to be added to the list — or just have a creative means of commemorating one of the dates above? Comments section, ahoy!

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