I've been becoming a fan of Node.js. Liberally licensed, V8 speediness, JS enjoyment. I haven't followed all the news, and I'd missed the recent great announcement of Microsoft helping with first-class Windows support. Also, while job listings for Node.js are still few, they are caught up to Erlang and keeping pace with Scala.
I look forward to JS replacing Java (and the JVM) all around someday.