My wife and I always make it a point to stir up the extended family during gatherings with various anti-India/pro-Pakistan/pro-Kashmir/ what-have-you rants. There is a lot of yelling and screaming, gesturing, drinking, eating... haven't won a single argument, of course, but nobody is ever left feeling empty or awkward ;-).
A few weeks ago, at a company "social hour", got into a huge argument with two women about affirmative action, etc (they were against it). So far, no fallout!
But you are right about the motivation behind the general tendency (clearly missing in me) of avoiding politics, etc.
--ravi