<< I once went on a date with this really shy guy.  FINALLY he began to talk, and it was all about the steps he used to clean his military rifle.  He went on for about 20 minutes, but he could or would not talk about anything else.  It was really, really awkward.  He just stared at me and I did not feel like talking much in that situation.
Like others mention, just talk about normal things -- and please do not assume that we dislike sports or computers or sci-fi or any other thing.  Talk about things that interest you and listen to what interests her -- it's that simple. If you get stuck, ask thoughtful, open-ended questions. >>
 Yes, exactly.  Don't assume they don't like things, but then again don't immediately drop that you're going to the next star trek convention and you're going in full regalia.  Wait until after a few dates when the other person is interested.  Then your interest becomes a funny "quirk" as opposed to something that will repel the woman.  As for the military guy, well we can't win them all can we?  Maybe he had something else on his mind that night, maybe you and him just didn't click, or maybe he just wasn't comfortable enough around women yet.  Everyone needs practice, and maybe you were one of the first people he'd actually been on a date with.