Walk around and kick the backs of their chairs HARD. Incite them to violence. Then when the cops show up, say, "How could I kick the backs of their seats? I was in row 4!" Or wait until they leave the theater, follow them to where there are no cameras or witnesses, and beat the fucking shit out of them.
Proper theater etiquette: Keep your mouth shut and your phone silenced and in your pocket or else you'll get your teeth knocked out.
But this was on the radio talk shows here (in Washington, where it happened) and most of the hosts were laughing about it.