I have always been interested in programming languages in general, and I have read books about quite a large variety (no, I am not saying that I am a professional in using those languages, just that I think I have a good overview). Recently, the interest in languages and language features (as opposed to bloated frameworks) has increased in the mainstream. Examples of somewhat advanced languages (compared to Java :-)) are Ruby, Scala, C# 3 (to some extent), Erlang (wrt. to concurrency) and of course the whole DSL movement.
I am currently writing a (german :-() article on that topic that I will post sometime in the future, but if you really want to get a good (and funny) impression of what it's all about, read The Last Language War / Language Trolling Post You'll Ever Need To Read (Hopefully)