February 29th: a leap year. When I was in primary school, I learned that the earth takes one year, or 365.25 days to revolve around the sun. I also learned that to make up for that "lost" day, we added an "extra" day, today, to the calendar every four years.
Then, in secondary school, I learned that the earth actually takes 365.242 days to revolve around the sun, not 365.25 days. This difference between the approximate value of 0.25 days and the more accurate 0.242 days (8/1000ths of a day or 11 minutes 14 seconds) may not seem like much, but it adds up to a little over one day every century.
I also learned that the Gregorian calendar that most of the world now uses adjusts this discrepancy of an extra day every century by adding an extra day only to those century years that are exactly divisible by 400. (The year 2000 was a leap year but the year 1900 was not.)
Even later, I learned that as a further refinement, every year that was evenly divisible by 4,000 would not be a leap year. This would keep the Gregorian calendar accurate to within one day in 20,000 years!
But where will I be in twenty thousand years? And what will I care? How many bodies will I have transmigrated through? All the planets and species of life in this universe are subject to the repeated misery of birth and death (abrahma-bhuvanal lokah punar avartino).
I must be conscious today, of the precarious predicament I am in, of just how tenuous this life is, and try to learn, in the association and service of Sri Guru and Vaishnava, how to purify my consciousness and live forever in the joyous, conscious service world (mam upetya tu kaunteya punar janma na vidyate).