Shrove Tuesday is the day before Lent begins when people historically have eaten pancakes to use up their perishable food like eggs and milk before the Lenten fast. It comes from the word shrive, which means to "confess" - as in confessing one's sins.
Another name for the day is Mardi Gras which is French for Fat Tuesday. This refers to the practice of the last night of eating richer, fatty foods before the ritual fasting of the Lenten season. However (or if) you celebrate it, I hope it is a good one where you are!