Shrove Tuesday

From BBC Religion and Ethics site

Shrove Tuesday is the Tuesday before Ash Wednesday which is the first day of Lent. It's a day of penitence, to clean the soul, and a day of celebration as the last chance to feast before Lent begins. Shrove Tuesday is probably the Christian festival that the family enjoys most, after Christmas, of course. But there's more to Shrove Tuesday than pigging out on pancakes or taking part in a public pancake race. The pancakes themselves are part of an ancient custom with deeply religious roots.

Penitence
Shrove Tuesday gets its name from the ritual of shriving that Christians used to undergo in the past. In shriving, a person confesses their sins and receives absolution for them. When a person receives absolution for their sins, they are forgiven for them and released from the guilt and pain that they have caused them. In the Catholic or Orthodox context, the absolution is pronounced by a priest. This tradition is very old. Over 1000 years ago a monk wrote in the Anglo-Saxon Ecclesiastical Institutes:
"In the week immediately before Lent everyone shall go to his confessor and confess his deeds and the confessor shall so shrive him."

Shrove Tuesday celebrations
Shrove Tuesday is a day of celebration as well as penitence, because it's the last day before Lent. Lent is a time of abstinence, of giving things up. So Shrove Tuesday is the last chance to indulge yourself, and to use up the foods that aren't allowed in Lent.

Giving up foods: but not wasting them
In the old days there were many foods that observant Christians would not eat during Lent: foods such as meat and fish, fats, eggs, and milky foods. So that no food was wasted, families would have a feast on the shriving Tuesday, and eat up all the foods that wouldn't last the forty days of Lent without going off. The need to eat up the fats gave rise to the French name Mardi Gras; meaning fat tuesday. Pancakes became associated with Shrove Tuesday as they were a dish that could use up all the eggs fats and milk in the house with just the addition of flour.