Let kids play
Allah tells the story of Yusuf’s brothers saying: "Let him go with us tomorrow so he can enjoy himself and play." (Yusuf: 12)
And it’s narrated that Hasan bin Ali used to play in the mosque of the Prophet Muhammad. (HR. Al-Bukhari 354 with similar wording)
(from Syajaratul Ma‘arif, Syaikh al-‘Izz bin Abdus Salam)