Why Mardi Gras???

To prepare for Lent and Ash Wed. of course.............
Ash Wednesday is the beginning of Lent for Western Christian churches. It's a day of penitence to clean the soul before the Lent fast.

Roman Catholic, Anglican, and some other churches hold special services at which worshippers are marked with ashes as a symbol of death, and sorrow for sin.

Symbolism of the ashes
The marking of their forehead with a cross made of ashes reminds each churchgoer that:

Death comes to everyone
They should be sad for their sins
They must change themselves for the better
God made the first human being by breathing life into dust, and without God, human beings are nothing more than dust and ashes