History - My fascination has grown as I have. History takes us on a fantastic ride to a different era - with different beliefs and "truths". Its also like a secret, magical mirror - looking back often helps predict the future.
  Productivity - My favourite procrastination. Organising stuff so that it functions like my external brain. GTD, 80-20, big rocks, minimalism - I love the stuff. Of course it is never perfect!
  Artificial Intelligence - This has been my draw as far back as I remember. This is what got me interested in Computers. Replicating the human brain, with all its memory, consciousness and emotions - that's the dream. This is why I do what I do.
  Cultural diversity - I love to think about this. The richness and variety across different cultures - we are spoilt for choice.
  Physics of the universe - Particularly quantum physics, relativity annd interstellar space. Awe-inspiring. To think that this is reality boggles the mind.
  The Unix design principles - I look to this whenever I find myself in a sprawling project and need to disentangle stuff.
  Google's architecture - Cutting-edge stuff. These guys are pushing the boundaries of software engineering and deployments.
  Classic Rock. Music with good lyrics. - This is just personal taste. Most of the songs of Pink Floyd, The Beatles, Kishore Kumar and Jagjit Singh appeal to me.