I speak Russian. Not fluently, but I'd say "very good". I never took any classes or even put a conscious attempt at learning it... My oldest sister has been living in Moscow for the past 25 years or so, and I used to visit her frequently (once or twice a year), and that's how I picked it up... Also my brother was married to a woman from Ukraine, and I was good friends with her (we lived in the same building, different floors), so that helped me to keep practicing the language when I'm not in Moscow. The woman is gone now (divorced), and I don't go to Moscow as often anymore, so I worry about my Russian skills weakening with time.
I can read Russian, but VERY slowly... It gets the job done though, I love using the underground metro in Moscow to move around, and you need to be able to read the signs and directions for that, which I can do. I can't write in Russian though.
I don't think it's a difficult language to learn, but I think I have a natural talent for learning languages (I currently speak four).
Good luck!