I was emailing a friend about this a few days back and thought it blog-worthy. When I was young, my family did something that we adopted from the book, "Cheaper by the Dozen". In the book, when one of the family members talked and talked about the same thing (annoying those around), another member would raise their hand and say, "Not of general interest". At that point, the rest of the family would vote and if indeed the majority deemed it as such, the initial person had to immediately stop talking about it.
Now, before you think, "That is so rude!", keep in mind that we really only did it to one another in a kidding manner, however it was followed through with! Think about it though, wouldn't it be grand if you could actually do this in everyday conversation with people? How many times have people gone on and on and you just wanted the conversation to end already??!! :)
p.s. Please don't think I'm endorsing the movie version of "Cheaper by the Dozen". It is so much worse than the book as it is full of snippy little snotty kids. The kids in the book were super respectful and the parents weren't portrayed as bafoons.