I don't know if this has been done before but who really cares, amirite?
It's simple. You say a title/quote/name bla bla bla from a tvshow/movie etc. etc. and then leave something out, indicated with a ______ . Then someone replies and fills in the blank.
Comment: "I'm _____, and I approve this message."
Reply: Ray William Johnson
Reply 2 (original commenter): Correct!
So have fun :D