I like to learn. Partly for the sake of learning and what it teaches me about me, but also because of the creativity that learning new things breeds. I like Coursera, Udacity and EdX courses because I am good at working to deadlines and I don't get motivated by badges or accumulating points. I'd recommend Geoffrey Hinton's Coursera course on Neural Networks for Machine Learning!
The common theme among the things I like to learn about is 'emergent behaviour' - when lots of simple systems interact to create complex behaviours. I like ants, slime mould and the brain where lots of simple biological systems interact to create complex outcomes. Ants for example are the most successful living insects and developed farming, both agricultural (fungus gardens) and animal husbandry (aphids and mealy bugs) millions of years before humans - that's right! Ants! I like cellular automata and Conway's Game of Life in particular as well as machine learning and AI.
Look some of them up and maybe you'll be as amazed as I was.
I also get to apply some of this because I work as a VC in London. I recently started using twitter and enjoy it. So if you want to get in touch tweet me :) @simonpking