There is a lot more behind it. Also called Shrove Tuesday, it marks the last day of the liturgical calendar before Lent begins. After Catholicism spread throughout Europe, many cultures celebrated the final day before Lent began in ways unique to that individual culture. Eggs, and milk were finished off in one day, giving rise to the term Fat Tuesday. In Poland, such things as lard, sugar, eggs, and fruit were forbidden during Lent, and the beloved pączki became a special treat for Fat Tuesday, and in Detroit they still sell many thousands of them to long lines of people.
Many people, Catholic and non Catholic alike celebrate Mardi Gras. Have a great day, but spare a thought to tomorrow.
No matter what church you attend, Lent is a custom, an observance, that you can use to prepare you to meet Christ renewed on Easter Sunday, with a deeper and more tested faith. Perhaps a faith better prepared to go into the world and share, model, and live the teachings.
By the way, I am sure most of you have seen us Catholics sporting the cross on our foreheads, traced in ashes blessed on Palm Sunday of the preceding year. Every parish will have one or more services to distribute ashes, and you do not have to be Catholic to attend and receive the ashes, should you so choose.