Clojure is far from the only language that supports both the JVM and CLR. I had a long reply ready, but I lost it. Off the top of my head the languages that have support on both (aside from Clojure) are; Python, Ruby, JavaScript, Java (though J# is being depreciated), Scheme, Common Lisp, PHP, Perl 6, Prolog, Pascal, Ada. I might be missing some.