The workings of the universe.
The workings of the human body.
Computer hardware and (to some degree) computer science.
Electronic music production (Especially with Ableton Live)
Business.
Philosophy.
Some sports, mainly basketball.
The diverse and interesting community here.
I'm actually amazed of how similar to me you are like we have the same first name and your interests are the same as me! Maybe John your some sort of universal port clone to me but your like an American variant of me.