Is Guess What a Question

Is guess what happened a question?

Guess what happened is a rhetorical tool and it does not ask you a question – it urges you to make a guess (most of the time it does not urge you to do anything at all, of course).

Is guess a question or command?

Q. How should the sentence “Guess what” be punctuated? I realize that it’s technically an imperative sentence, which should end with a period (or exclamation point), but in many contexts it’s used as if it were interrogatory, and thus it’s often punctuated with a question mark rather than a period.