Typically - at least in Chicago - you just need to bring them to a game to win them over. Yeah, the quality of the play isn't up to a major Euro standard, but it's a great day out. I had a friend who's a "dyed in the wool" ManU fan (for like...a year now) come to a Fire game last season. He's now a season ticket holder.

Unless of course, they're a titanic douche and can't see that. Either way, support your local team. Most of us have favorites in other leagues, I know I do, but they fall far, far behind the Fire.