How do you find a Passion?

I think I've discovered that I don't really have a specific passion.  Luis is lucky enough to have found 2.  He played soccer for most of his life and was very good.  He was nationally ranked in High School and played College soccer.  He quit soccer about 2 years ago when he found a new passion in MMA.  He is so incredibly dedicated, training about 30 hours a week and making sacrifices to do what he loves.  I am very proud of him, but I do  envy the fact that he is so passionate about something.

I don't really have anything that I am that passionate about.  I like to do a lot of things but I wouldn't say I have a true passion.  I think I should try and find something that I could devote such time and energy into.  But how?  Luis didn't go out looking for a passion, he just stumbled upon it.  So I'm thinking that I need to dig deeper into the things I like to do to see if I can zero in on something that really gets me excited.  I really enjoy working out, testing my body and my mind so I'm thinking I should try things that are physical.  Maybe a triathlon, or long distance cycling or maybe even try my hand at boxing or Muay Thai on a more serious level.  To me this seems like a good way to kill two birds with one stone since I am really trying to get into really good shape.  So I am on a quest to find something that I am truly passionate about.  Hopefully, I find something soon =)