愚人节（April Fool's Day或All Fools' Day）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，日期在每年公历的4月1日。
在这一天人们习惯以各种方式互相欺骗、捉弄及取笑，而往往玩笑在最后才被揭穿。但如果玩笑开得过大，则很可能会引起人们的恐慌，产生较大规模的反响及进一步衍生成为谣言或都市传说等。
英语作文愚人节故事带翻译：
April Fool Last March, my mother told my father and me that my grandfather would come in April. We were very happy because my grandfather was an interesting old man and he had not visited us since he went to Hong Kong. On April 1 my father and I bought a lot of food from the supermarket and bought a big bunch of flowers home. Then we did some cleaning at home. At night when we were waiting for my grandfather, the bell rang and in came my mother. She smiled to us and said "April fools"!
去年三月的愚人节，我母亲告诉我父亲和我，我祖父会在四月来。 我们非常高兴，因为我的祖父是一个有趣的老人，他没有访问我们，因为他去了香港。 4月1日，我和父亲从超市买了很多食物，还买了一大束花回家。 然后我们在家里打扫了一下。 晚上我们在等爷爷的时候，门铃响了，我妈妈进来了。 她笑着对我们说”愚人节快乐” ！