Spanish I read quite a bit and crossed the beginner level. Now I am thinking to spend weekly 2-3 days to pick up some language skills - as a hobby! Indeed, there are so many languages in the world that one lifetime is not enough. But, I can try out some, like Arabic, Spanish, German, Italian and if I am alive after that - CHINESE :).
Intentionally the hardest of them is last. It takes 2-3 years to actually get hold of chinese, I heard. So, let's build some confidence with 2-3 languages first and then give a digg at Chinese.