Practical strategies for increasing one's passion and excitement about research? I am a second year PhD student in computer science. I see other students craving to find new problems, read papers and it's like they are enjoying it and when they find a problem, they spend endless hours trying to come up with a publishable results about it. 

I talked to some people and they said, many times you get to like what you do, it's not that you always end up doing what you like - implying that this kind of excitement and motivation is something that can develop in time.

Can you give me some practical strategies that help towards gaining and maintaining a high level of excitement and motivation about research? What keeps researchers like those I described constantly interested and excited to do research?
I find that a good way (for me) to get excited about my research is to work with some inexperienced research students - high school and undergraduate students.

Mentoring these students reminds me of the things that excited me about research when I first started: mainly, that we can come up with some problem that we think is interesting, that hasn't previously been solved, and then go ahead and solve it. I still think that is so cool, and seeing that reaction in my students reminds me all over again :) Also, I get to feel like an expert in this scenario, which helps makes me more excited about my work.

Generally, I find that spending time with others who are passionate and excited  encourages those feelings in me, too.