"Ку-ку" is a popular children's game often played to engage and entertain young kids. The game typically involves one person hiding and then surprising others by popping out and saying "Ку-ку," which translates to "peek-a-boo" in English. It helps develop social skills and encourages interaction among children. The game is simple and can be played anywhere, making it a favorite among parents and caregivers. It is often used to teach children about object permanence, as they learn that even when they can't see someone, that person still exists. This playful interaction fosters bonding and joy.