Pi Day
From Tardis Wiki, the free Doctor Who reference
Pi Day fell on 14 March annually, so called because the date looked like the ratio of the circumference of a circle to its diameter, 3.14. As Pi actually had infinite digits, true Pi Day could only be found on planets with a far more complex calendar. (PROSE: Time Traveller's Diary [+]Loading...["Time Traveller's Diary (novel)"])
