What a talented bunch here
My main hobby has always been drawing, been stuck to a pencil (or a Wacom tablet these days) since I was a little girl. It's all casual although I have done some commissions through the years and been part of a few shows. While it's related to my love for design, pure illustrative work is my main way to relax and I like to keep it that way. I find it really different from visual/graphic design. I also have a Tumblr sketch blog, updated somewhat sporadically.
I also practiced the piano for 10 years and have one at home, so classical music has always been a big part of my life. Yet another way to zone out, mostly, but I also feel richer for having learnt music history and theory.
Mythology and ancient history/languages is yet another hobby, although somewhat related to my studies in Historical Linguistics--my Master's thesis was an etymological research on various nature-related female deities in Norse Mythology. But I'll eat up anything that's ancient and languages with a foreign alphabet get brownie points!
As for more odd "skills" (hesitant about that word here!), I'm a big geography nut and love learning various facts about countries, be it cities, nature, typology etc. Reciting the top 30 cities in China or India is a good brain exercise, at least!
Ending on a more convenient note, I love cooking, travelling, doing yoga, long conversations with close friends and reading, mostly non-fiction.