I think that sports gives many people an excuse for thinking and talking. You can read about it (every paper, no matter how lousy, has a sports page), it's impossible to know all the facts (who hit into the most double-plays in 1983?), there's plenty of room to have an opinion (Gretzky or Esposito?), and it's easy to specialize in something so that, when it comes up, you can participate.
I keep a couple of gems in my back pocket for use in such situations (buy me a beer if you're curious!).
/jordan