It's YOUR day to EAT all you want, DRINK all you want, SEX it up, get all debauched up and generally let loose*!
In other words, it's live like a Sheen day! PARRRTAAYY
* The reason for this is because Lent starts tomorrow with Ash Wednesday and so starting tomorrow we are supposed to be "good" people and give up something as a sacrifice for the season. This all leads up to Easter, when we can celebrate the death of Jesus (oops! The Resurrection of Jesus! How do we always get that confused? Sorry!) and supposedly eat a lot again. So enjoy your "FAT TUESDAY" before you start sacrificing for God.