Opposite Day

Opposite Day is a holiday, observed on April 30, where every action is modified so that meaning is inverted. Once Opposite Day is declared, statements mean the opposite of what they usually mean. Usually, a person would say, "After this phrase is over, it will be officially opposite day," and then Opposite Day will be officially started. Opposite Day can also be declared retroactively to indicate that what was just asserted had the opposite meaning of what was originally intended (similar to the practice of crossed fingers to automatically nullify promises). Play has been compared to a children's "philosophy course", and the game has been used as an educational aid and suggested as preparation for "standardized testing".