Also known as Shrove Tuesday in English-speaking countries and even Pancake Day, it is traditionally a day of feasting before Ash Wednesday, which marks the start of the fasting season of Lent.
In Germany, the celebration is known as Karneval, Fastnacht or Fasching, depending on the region.
In France, it is called Mardi Gras (Fat Tuesday). In Australia, Mardi Gras has a completely different meaning, devoid of the original Christian religious reason, but then so are celebrations in New Orleans.
Happy Fat Tuesday.