Shrove Tuesday is the day before Ash Wednesday (the first day of Lent), celebrated in some Christian countries by consuming pancakes; in others, especially those where it is called Mardi Gras or carnival day, the last day of “fat eating” or “gorging” before the fasting period of Lent.
Shrove Tuesday is observed by many Christians, including Anglicans, Lutherans, Methodists and Roman Catholics, who “make a special point of self-examination, of considering what wrongs they need to repent, and what amendments of life or areas of spiritual growth they especially need to ask God’s help in dealing with.”
The expression “Shrove Tuesday” comes from the word shrive, meaning “absolve”.
In Lent, many Christians commit to fasting, as well as giving up certain luxuries in order to replicate the account of the sacrifice of Jesus Christ’s journey into the desert for 40 days; this is known as one’s Lenten sacrifice.
Sources: Wikipedia