This year, the "official" date of Mardi Gras was yesterday, February 28th. Mardi Gras is among several "holidays" that are calendared using a lunar rotation. Next year it falls on February 13th, and the year after that, March 5th.
A few other fun "Mardi Gras" facts:
Mardi Gras is celebrated world-wide, is often referred to as "Carnival" and in some countries is an official non-work holiday.
The literal translation of Mardi Gras from the French is "Fat Tuesday."
In some parades it is illegal to be on a float without wearing a mask.
New Orleans starts their Mardi Gras celebrations the day after Christmas!
Some groups of revelers choose a "Capitaine" to travel with them as they party their way through streets and neighborhoods. The Capitaine is responsible for controlling the ensuing chaos. Much like a designated driver, the Capitaine pledges not to get intoxicated, and often does not wear a mask.
The origin of Mardi Gras beads and their meanings was determined by Rex, the King of the first daytime Carnival in 1872. Rex was really Russia's Grand Duke Alexis Romanoff. Being of royalty, he determined that he would use the royal colors for this celebration: purple for justice, green for faith, and gold for power.
New Orleans holds children's parades, where float participants throw not only beads and candy, but thousands of toys and stuffed animals along the parade route.