fun and games

Noun

idiomatic often plural plural-only used ironically

(idiomatic, often used ironically) Recreation; nothing serious; easy, enjoyable activities.

Japanese Meaning

軽い娯楽、気軽な遊びといった、深刻さを伴わないリクリエーション活動。 / 何事も本気にならずに楽しむ、単なる余暇や遊びの時間を意味する表現。

Sure, organizing a surprise party sounds like fun and games until you have to clean up the mess.

確かに、サプライズパーティーを企画するのはただの娯楽に思えるが、後片付けをしなければならないと分かると話が変わる。

Sense（1）

(idiomatic, often used ironically) Recreation; nothing serious; easy, enjoyable activities.

Being a film director isn't all fun and games.