Clojure on the Apple Runtime.
But I’d love to see Apple extend this. One of the awesome things about .NET and Java(the real kind, not the Android thing) is that the virtual machine or the run time is designed in a way where you can use Java libraries in other programming languages running there, without having to implement specific packages allowing it.
I want to write native iOS and Mac apps using Clojure. Someone else might want to do so using Ruby or even PHP. I have no idea if this is possible with the current iOS or Android runtime, but I’d love it if we moved against a world where all the app development stuff wasn’t so tied two a couple of programming languages on each platform.