Recipe for figuring the date of Mardi Gras Day: Start at Easter. As you know, the date of Easter can vary greatly. Forty days prior to Easter (not counting Sundays) is Lent. The first day of Lent is Ash Wednesday. The day before Ash Wednesday is Fat Tuesday – Mardi Gras Day, which is the final day of the Mardi Gras season. The official beginning of the Mardi Gras season is Jan 6, which is called Twelfth Night (12 days after Christmas). On that cold night, a krewe called Phunny Phorty Phellows has their drunken streetcar parade down St. Charles Ave. For more info on Mardi Gras, see our ebay store. We're using the money from the Mardi Gras auction to help the businesses.