In America it is known as Mardi Gras and it is traditional to eat a King Cake.
In England the day before Lent in called Pancake Day and growing up my mother would serve as many pancakes as I could eat for dinner that night.
I top it with sugar and lots of lemon juice.
I use Delia Smith's recipe , but its basically the same as a crepe if you have a recipe that you already love. Just remember to smother in lemon juice, and then sprinkle with sugar.