Fat Tuesday is Mardi Gras, the festival New Orleans, Louisiana, is famous for. "Gras" is French for fat and "Mardi" is French for Tuesday.
The annual festivities start on January 6, the Twelfth Night Feast of the Epiphany, when the three kings are supposed to have visited the Christ Child, and build to a climax on Mardi Gras, or Fat Tuesday, which always occurs on the day before Ash Wednesday. The parties and parades will continue until Lent begins at the stroke of midnight on Tuesday.
Mardi Gras is a legal holiday in New Orleans. It is scheduled to occur 46 days before Easter. Since the actual date Easter occurs on changes yearly, Mardi Gras can happen on any Tuesday between February 3 and March 9. For two centuries it has been an annual event in New Orleans, except during the two World Wars.