The French are known for many things; their rich culture, the beautiful language, the romance; but let’s not forget–their humor. Every April Fool’s Day, is it customary for the French to slap a fish on an unsuspecting friend’s back. Of course, it’s only a paper fish, but the friend is then the poisson d’avril, or the fish of April.

This year, the French Club is celebrating with a fish-designing contest, in which students can take a paper fish cutout from room 240 and create a unique design for it. The winner will have their design displayed on the fish for poisson d’avril and from there students can take part in the French tradition and slap their friends on the back.

It’s said that the tradition of April Fool’s actually originated in France, as a French travel guide explains the beginning of the joking custom. The theory goes like this: In 1564 King Charles XIV of France reformed the calendar, moving the start of the year from the end of March to January 1. However, in a time without trains, a reliable post system or the internet, news often traveled slow and the uneducated, lower class people in rural France were the last to hear of and accept the new calendar.

Those who failed to keep up with the change or who stubbornly clung to the old calendar system and continued to celebrate the New Year during the week that fell between March 25th and April 1st, had jokes played on them. Pranksters would surreptitiously stick paper fish to their backs. The victims of this prank were thus called Poisson d’Avril, or April Fish—which, to this day, remains the French term for April Fools—and so the tradition was born.

While it is not clear of the origins of fish being associated with April 1, many think the correlation is related to the zodiac sign of Pisces (a fish), which falls near April. Nonetheless, to this day, people in France celebrate by decorating fish and slapping them on stranger’s backs, and bakeries and shops set out fish shaped treats.

If you’d like to participate, be sure to look out for the fish; they’ll be distributed on April 1st slapped on the back, there’s a chance you will win a tasty prize!