Today is 3.27, so it must be time to celebrate the Lévy constant! The Lévy constant describes the asymptotic behaviour of the denominators of convergent continued fractions.
Continued fractions are those numbers created by an iterative process of writing out a number as the sum of it's integer part and the reciprocal of another number, which is itself written as the sum of it's integer parts and another reciprocal, and so on until your head explodes.
If a continued fraction eventually hone in on some number, then it is a convergent continued fraction. In that case, the bottom part (the denominator) of all those fractions are asymptotic, which means if you graphed them, they'd form a curve approaching but never reaching a line.
...yeah, it's an obscure one. But during the group discussion on the far-more-popular Pi Day, I did promise to throw my support behind
as whimsy demanded. Anyway, we're not alone: IEEE Spectrum is also celebrating Lévy Day!
Images via uncredited creative commons; thank you, generous strangers!