People go to bars and have conversations that they find pleasant. You need to go and have conversations that you find pleasant, which for you probably means stimulating and informative. You're probably talking to people who like different kinds of conversations. Find new people!

Alternatively, get interested in people themselves instead of just what they talk about. Every conversation can be mined for information about the person you're talking with. I'm working on this myself by reading Studs Terkel.