Here's an exercise I just came up with as a method to expand and pivot my passions. Start out with something that excites you, something that you're really passionate about. Visualize that this activity or idea is just a lake that's part of a big network of lakes, rivers, streams and oceans of passion. An example for me is running the Madison PHP Meetup Group.
Next start asking yourself questions. Why is this important? What about this jacks you up? Is this a subset of a larger passion of yours? We need to swim into the other bodies of passion that feed into or out of this idea. For my example I love running the PHP group because I enjoy teaching and helping people, solving problems, learning new things and sharing what I know.
Repeat the last step a few more times. Ask more questions not only on the original idea but on all the related ideas that you're discovering. Pick some other things that you're passionate about and work through the exercise on those ideas too. You'll probably start to find overlap between things. These are your core passions. Other things I'm interested in are self development and entrepreneurship.
Once you have a giant list of ideas and activities and passions try to organize them. One way could be creating a mind map so you can look at how every idea is related.
The final step is to start coming up with some new ideas and activities. This can be done by finding patterns in what you see or by expanding or refining the ideas you already have. You're not trying to find more things that you're currently doing, but rather new things that you would probably be passionate about if you were doing them. These ideas can be things to strive for or to start working on. For myself since I like teaching and helping people and I'm also interested in entrepreneurship I'd probably be very passionate teaching entrepreneurship. Now I'm not currently qualified to do this, but it's something that I could start working on.
Why is this useful? If you're someone like me who's interested in starting their own business, you'll be happier doing something that you're passionate about (and probably more successful). The larger the pool of passions you have, the more chances you'll have to find one that can be built into a profitable business.