I love moonscript, it makes lua feel so much more usable for me. Admittedly, I'm mostly only using it for convenience in configuring apps(such as my WM¹/video player²/etc).
If you want to see a large-ish example of what you can do with moonscript the howl editor³ is a great example. It is also a nice extensible editor in its own right, including a very usable vi mode.