Rooted in playground tradition. A fictional holiday, in which everything you do or say means exactly the opposite. Often used at the end of a sentence to negate what you just said.

A fake holiday where you do exactly the opposite of everything.

Obviously is wrong in itself, because if everything is opposite, than opposite day cannot exist. And no, it can't go the other way, obviously, since there is no opposite day.

Try this logic with 4th graders.

A day where everything you say means the opposite of what it normally would. Kinda juvenile, but its fun too.

Opposite Day is a fun "game" played on another. You never know when this day takes place, but when it does, everything you say has the opposite meaning of what it would on a normal day. The quest is on to figure out when this day actually happens, so you can safeguard yourself from its horrors.

(march 27th! or so i've heard hehe.)

a day when "no" means "yes" and "shut up" means "keep talking" and etc..u do the opposite of what someone tells u to do.say the opposite things.blah blah blah.

Opposite day isnt a real day, where you dont do the opposite. People will say nothing opposite. Every other day of the year IS an opposite day.

Oh, and you musnt be reading this on opposite day, or youll understand it. :( (and yes, the smiley isnt opposite)

Celebrated on April 30th, the opposite of April 1st. The day when you are nice to your boss, teacher, enemy and can be a complete Ahole to your best friends. You can just say the opposite of what you want to say, and confuse/laugh at all the people who dont know why you are saying what you are saying.

Because April fools, has become a cliche.

Also spelled yad etisoppO, and occipatai