Suggestions to shut up yappers at the theatre

[mdtulp]

Whats some unique or best ways you've ever told some one to "shut up" at the theater? Last Night at Iron Man, two teenage girls were driving me nuts, just consistently yapping during the previews and the movie, I've never been able to blurt stuf out that I wanted, and of course you dont wanna yell out "Shut the F up juno" at youngsters, Just wonderin if any of you have a response to these type of people? What you usually say, or somethin hilarious that will get the point accross without sounding too threating