I've found that in order to really pick up a new language, paradigm, library, or platform, I HAVE to do some real work. I can't just sit there and start typing up something. Some people like Project Euler as their own rosetta stone for this kind of thing, but I don't.
I always need tools or little one-off programs so I forced myself to write them in Common Lisp and then Clojure and it really helped me.