Anything. There's barely a subject, maybe football and cars, that I can't talk about well.
No matter if philosophy, politics, sports, movies, series, music or anything else, as long as you can talk about it reasonably on a good level, I'm there!
I love the Harry Potter novels. There's hardly a place in the movies I can't memorize and hardly a chapter where I can't say exactly what's happening. I like to listen to the audio books to fall asleep, the whole world is so impressive and a fascinating place to retreat.