>>How about this one? In that same theater:
>>
>>- IS THERE A DOCTOR IN THIS THEATER?
>>
>>- Yes! I am a doctor.
>>
>>- So, doc, how do you like the movie so far?
>
>Too much Marx Brothers lately?

Didn't know it was them. Wouldn't expect it either - weren't they supposed to be on the screen and not in the audience?

Came through someone on a forum, equally ignorant of the origins as I am.