I realized a few months ago that I was talking too much in conversations, and not listening nearly enough. So for the last few months, I've decided to talk a lot less, and spend a lot more time just listening to people. In one on one conversation, I mostly just ask the other guy about the things he's talking about, to lead him into deeper (perhaps more interesting) areas. This is a great way to talk about interesting…
I am a very good listener, and enjoy listening at least as much as talking. If you figure out how to get someone monologuing, they'll eventually stumble into territory you find interesting. You just have to 'convince' your conversant that it's OK to dive deeper into a topic. Ask them to elaborate or explain things that sound interesting. Try to show you're interested and intrigued.
This tactic has helped me befriend people I would never have thought twice about if I'd dismissed their casual conversation as uninteresting. People I have absolutely nothing in common with. I've engaged in fascinating, enlightening conversations and lectures on philosophy, programming, design, cooking, life, finance, and more. Some of these conversations were life-changing, and it's all because I pushed the buttons that got people talking deeply about their interests.