I think i've mentioned this before, but a few years ago I was watching a movie at the Showcase in Dudley and this utter word removed and his missus hadn't stopped talking (loud, not whispering) since they had sat down.
About twenty minutes in, i'd had enough and made like I was getting up to go to the loo but instead just stood up and stayed where I was. Sure enough, after 10 seconds or so Mr.Chatty Bollox says 'can you sit down?' to which I turned and replied 'yeah of course mate, as soon as you shut the **** up'.
After a brief grumble to his missus he shut up and I sat back down. Job done.