A yo-yo is a toy that consists of a length of string tied at one end to a flat spool. Despite its seeming simplicity, a yo-yo can provide hours of fun and challenges because with practice, many cool yo-yo tricks can be mastered and performed.
As it is so small, a yo-yo is an easy toy to sneak into school. Children then try to outperform one another during recess and they practise hard to put up a good show. Because of the competitive nature of this game, yo-yo contests are occasionally held at shopping malls. Yo-yoing is a game that has stood the test of time and it continues to be popular with both children and adults alike.
Read more: https://en.wikipedia.org/wiki/Yo-yo