Google Go is an other interesting recent language although honestly I’m not sure how much in use it is. I believe Google uses it but I don’t know how much others do. One that I’ve actually been curious about learning is Clojure – a Lisp variant – although I’ve just not had enough time yet.
It’s interesting to me that most new languages end up being variants on older languages – primarily C/C++, SmallTalk, and Lisp (or combinations of the two such C + Smalltalk as Obj-C). Then there are the languages you just don’t hear much about now such as Forth. Fortran’s still around, heavily expanded from the Fortran I learned in my youth. One that I’ve never seen much is APL although it did influence mathematical languages like Mathematica or MatLab.
Still the last real significant language introductions that I know are Ruby and Python. (PHP counts but was already popular in the late 90′s whereas I remember Python really getting popular only after Python 2 was released – others might disagree)