I plan to commemorate the upcoming Hobbit Day by reading my still-unopened hardcover edition of *Children of Húrin*. But then it struck me: we went through all of August without a single nerdy day. In fact, several months find themselves bereft of well-established dates to signal your obsession or social awkwardness.

## What we have

**Pi Day**, celebrated 14 March, and so named because the decimal expansion of the mathematical constant pi begins with 3.14. Amazingly, there is a resolution by the US Congress that actually “supports the designation of a ‘Pi Day’ and its celebration around the world” [H.RES. 224 at Library of Congress] The date also coincides with Albert Einstein’s birthday, which makes it even cooler.

**Star Trek Day**, celebrated 5 April, commemorates First Contact with the Vulcans. There is an alternative day commemorating the first airing of a Star Trek episode, but I don’t like out-of-universe explanations. 5 April it is.

**Star Wars Day**, celebrated on 4 May because the phrase “May the force be with you” can be misheard as “May the 4th”. (This mishearing apparently really happened to a simultaneous interpreter on German TV in 2005, see Wikipedia. Learn something new each day.)

**Geek Pride Day** is celebrated on 25 May, though seems to be only sporadically observed. It unifies several geeky days, including Towel Day for *Hitchhiker* fans. Look it up.

**Pi Approximation Day** is celebrated 22 July, since 22/7 (in the day/month format) is a well-known approximation of pi. Of course, 3.14 is also just an approximation, and only ever so slightly closer to the real (ahem, irrational) value of pi than the fraction 22/7. But “Pi Approximation Day” and “Slightly worse pi approximation day” doesn’t have the popular appeal.

**Hobbit Day** is celebrated somewhere around 12 September. It commemorates Bilbo’s and Frodo’s birthday, and due to delicious discrepancies between the fictional Shire calender and the Gregorian calender, the actual date is a matter of entertaining and serious debate among the cognoscenti. Just as we like it. It’s as good a day as any to discuss whether Balrogs have wings. (They don’t.)

**Mole Day** is celebrated on 23 October, preferably at 6:02. This gives 6:02 10/23 in some time format, mimicking the value of Avogradro’s constant 6.02×10^{23}. I don’t like that the solidus in 10/23 is used to denote exponentiation, but it’s a day for chemists anyway. Chemists don’t do rigour.

These are good days to connect with your inner nerd, geek, or scientist. Or just have some pie. But it leaves several months of the calendar completely empty! Except for some years, where there could be a lucky hit from **Square Root Day**, which falls on 4 April 2016 next. (4.4.16. Get it?)

## What we need

Here are some suggestions:

**E-Day** on 2 July. Not very inventive, I’m afraid, merely mimicking pi day with only a single digit in the decimal expansion. But e is at least as interesting number than pi, except for the pie. We could call it Napier’s or Euler’s day instead of E-Day. Or natural logarithm day? Activity: learn to use a slide rule. Hm…

**Imaginary Day**. This idea is only half-baked and came up over lunch. The idea is to celebrate Imaginary Day on 28+i^{y mod 4} February in year *y*. In leap years, this is 29 February, the leap day. Two years later and before, Imaginary Day is celebrated 27 February. In the remaining years the day is in fact imaginary (since we don’t have complex valued dates), but I propose to project the date on the real axis and celebrate 28 February. You would use Imaginary Day to learn about complex arithmetic and reconnect with your imaginary friends.

**Turing Day** celebrates Turing’s birthday on 23 June. Alternatively, we could take two days earlier: on 21 June 1948, the Manchester Small-Scale Experimental Machine (“Baby”) ran the first stored program. This implements Turing’s universal machine, envisioned in his 1936 paper.

**Perfect Day.** I’m a little bit proud of this idea. I suggest to celebrate it on 28 June, the only date in the year where both counters are perfect numbers; 6 and 28. And Perfect Day just sounds like a, well, perfect day. Make it extra special for yourself or somebody else.

**Programmer’s Christmas**. This idea is not mine, but since 31 October is 25 December to programmers. (Programmers are used to think in the octal number system, and 31 in octal (or, OCT) equals 25 in decimal (or, DEC). Hilarious, at least before I explained it.) Unfortunately, it’s in October, where we already have Mole Day.

This still leaves several months wide open. Should we *really* celebrate Unix new year on 1 January? Any ideas for August, November, December?