I'm a Finnish biologist, though you don't see me editing the biology-related articles all that much. That's work, I come to Wikipedia to relax.
My other areas of interests include (in no particular order), comics, natural sciences, feminism and science fiction. What I mostly do here though is wikifying and little tweaking here and there. I usually browse the Recent changes list and click to articles that catch my attention (the most usual reactions being either "What the heck is that?", "I always wanted to know what that is." or "What on earth could they be writing about that?"). Only seldomly do I manage to keep my finger off the edit button (to me, wikifying articles is much like popping bubble wrap).