The word "shrove" refers to the hearing of confessions.
"In the week immediately before Lent everyone shall go to his confessor and confess his deeds and the confessor shall so shrive him." (Theodulphus)In Germany, (and areas near me in Pennsylvania), Shrove Tuesday is known as Fastnacht or, the eve of the fast. Instead of making pancakes, a German Fastnacht tradition is to make donuts. My grandmother used to make her own donuts on Fastnacht.
The resulting frenzy to use up all the foods forbidden during Lent, gave birth to Carnival and Mardi Gras. Carnival comes from the Latin carne levare, or "taking away of flesh", which could refer both to the prohibition on meat eating, as well as the resulting submission of one's own human nature to things above.
Mardi Gras is French for "Fat Tuesday" and has taken on a life of its own in places such as New Orleans, in the U.S.
I'll admit that my foray into Anglicanism will make me forever see the day before Ash Wednesday as Shrove Tuesday.