How to start a conversation with a guy?

OK there is this guy that I'm interested in and he seems really cool and an awesome person. He's from Wooster, OH about an hour and a half from where I live and his career is really cool(races sprint cars and motorcross). He doesn't know me at all but I've seen him before and got my picture with him and he did accept my friend request on Facebook. So the next time he's online what should I say to him. Something that will make him reply back. THANKS!!!!!!!!!