How do you avoid discussing anything non work related at work?
The interest around politics may have peaked after the debate in the US, but in Greece politics (and more specifically the economy) is what everyone is interested in discussing for at least the past couple of years. You'd imagine that it would be far more difficult for us to avoid such discussions, but it really isn't. Just don't talk about politics yourself, and politely excuse yourself from the company when someone else starts the discussion.
Coincidentally I've worked in two environments which can be considered polar opposites when it comes to discussing politics, one was a town hall (where politics were actually our work) and the other was the Army (where discussing politics is strictly forbidden).
Couple of years after I left my position at the town hall, that involved regular meetings with elected officials, my co-workers there were surprised to find out that (at the time) I was a supporter of a minor opposition party. I had spend nearly seven years in an environment where politics were all there was to talk about without disclosing my own affiliations. I just never talked about it ;)
Every workplace is different, but I don't think that in a typical workplace there's much room or time for non work related discussions. Certainly we all take a break once in a while, and we all might get caught in an uncomfortable discussion around the water cooler, but those discussions tend to be short (how long can your break really be?) and easy to evade. My standard excuse when things start getting uncomfortable, or I'm simply not interested in the discussion, is that... I have to get back to work. Simple, isn't it?