Shrove Tuesday (AKA Pancake Day, AKA Mardi Gras)

"Shrove" is the past tense of "shrive," to confess.  I shrive; I shrove; I have shriven.  Shrove Tuesday, then, is "...a day of penitence, to clean the soul, and a day of celebration as the last chance to feast before Lent begins..." on the next day – Ash Wednesday. (What Does It Mean)   Ash Wednesday, of course, is the day when the faithful are marked with a cross on their forehead made from the blessed palm ashes from the previous year's Palm Sunday.  Not only does this show one's sorrow for her or his sins; it also marks "the need to prepare for a holy death." (What is Ash Wednesday)

Ash Wednesday always falls 46 days before Easter.  When Easter falls, however, depends on the moon.  Easter is "...celebrated on the first Sunday that occurs after the first full moon on or after the vernal equinox,” which is also known as the Paschal, or Passover, Full Moon. (Paschal Full Moon)  46 days before that can be anywhere from as early as February 3 to as late as March 9.  (Castelow)

Technically, though, Lent only has 40 days, which ties into "...the traditional number of judgment and spiritual testing in the Bible (Genesis 7:4, Exodus 24:18, 34:28, Numbers 13:25, 14:33, John 3:4)."  In particular, "Lent bears particular relationship to the 40 days Christ spent fasting in the desert before entering into his public ministry (Matthew 4:1-11)."  As such, Catholics are attempting to "...imitate Christ by spending 40 days in spiritual discipline before the celebration of Christ's triumph over sin and death."  (Why Do Catholics Practice Fasting and Abstinence During Lent) 

The other six days of Lent are Sundays, which are considered "feast days." (What is Ash Wednesday)  Therefore, Catholics are not required to fast on Sundays during Lent.  Indeed, some authorities believe it is biblically forbidden to fast on Sundays, because Sunday represents the day Christ was resurrected, and should always be a day of celebration.  (Should Catholics Fast On Sundays During Lent)  Now there's a technicality I wish I knew when I was a child, suffering without candy during Lent.  Go ahead and have that Snickers Bar.  It's Sunday!  As far as that goes, Catholics are not required (at least, not any longer) to fast during Lent at all, with the exception of two days:  Ash Wednesday and Good Friday. (Should Catholics Fast On Sundays During Lent)

And that abstinence, or fasting (whether you technically need to or not, or even whether you intend to or not), led to Pancake Day.  It's pointless (or so Sister Theresa would argue) to give up those things for Lent that you aren't indulging in to begin with, such as cigars, prostitutes, and crack cocaine.  Therefore, traditionally, people gave up those things they enjoyed, the "luxuries" of life, which included such things as flour, butter, and eggs.  The flour might keep for 46 days, but the eggs and butter... probably not.  So they feasted on all those perishable items on Shrove Tuesday.  And if you have flour, butter, and eggs, you've got pancakes.  Further, because those "luxuries" were those "fatty" items, Shrove Tuesday became known as "Fat Tuesday," or, in French, "Mardi Gras." (Willis)  So if you are giving up those luxuries of life for Lent, and one of those luxuries happens to be alcohol, then why not be hungover for 45 of the next 46 days?  Mardi Gras is the second most "drunken" holiday, following only the Super Bowl.  (The Top Ten U.S. Drinking Holidays)

In 2021, Shrove Tuesday falls on February 16.  Luckily, Ash Wednesday does not fall on Valentine's Day, which would create quite the quandary if you're giving up sex for Lent (like people have ever given up sex for anything).  Or, you can just make it easy, and give up Lent for Lent, which is something Sister Theresa probably wouldn't've approved of, either.