愚人节也称万愚节、幽默节，愚人节节期为公历4月1日，是从19世纪开始在西方兴起流行的民间节日，并未被任何国家认定为法定节日。在这一天人们以各种方式互相欺骗和捉弄，往往在玩笑的最后才揭穿并宣告捉弄对象为“愚人”。玩笑的性质极少包含实质恶意，但个别玩笑由于开得过大而引起人们的恐慌，产生较大规模反响及衍生成为（传媒）谣言和都市传说，所以对于人们来说一般会加以避免如灾难之事的玩笑。
April Fool's Day is also called "April Fool's Day" and "humorous Festival"、 The fool is gradually on the Gregorian calendar、 In April 1st, it began in nineteenth Century and became a popular folk festival in the West、 It has not been recognized as a legal holiday by any country、 On this day, people cheat and make fun of each other in various ways, often at the end of jokes only to expose and make fun of "fools"、 The nature of the joke rarely contains substantial malicious, but individual joke because of too much opening caused panic, produce larger repercussions and become (media) rumors and urban legends, so for people will generally be avoided if disaster that joke、