I think many of the "fun" ones will always be tarpit ideas. e.g. "an app to help find something fun to do with friends"... that's just your chat app of choice.

Instagram has recently been quite successful at giving me ads for events that seem actually fun and relevant to me, to the point of me being low key afraid of throwing off the algorithm so it starts recommend worse things. So, I think there's potential but it's very elusive. I feel that my Instagram "getting it" is more of an accident than by design.