Asking in-depth questions related to the other person's story is a great way to keep a conversation going. Really listen to what the other person is saying and ask the relevant questions, as if you're interviewing them. It might take some practice, but it works wonders. People absolutely LOVE it when someone else is really listening to them intently, it will easily create a sense of connection.

There's an article inspired me to start doing this a few years ago, and it has really helped me in social situations (even with the ladies, which I'd not expected). If you want to take a look, google for "How to Always Have Something Better to Talk About Than the Weather" and read the article on Raptitude. I can't post links yet.