I love the SteamFace Machine UI -- you don't see interfaces made with that level of care and artistry often any more.
It looks a really nice library, somewhat surprised I haven't heard of it before, but glad it's getting upvotes on HN now!
I spent a short amount of time reading about the scripting language. It's a pipeline of commands and seems very powerful, but I haven't grokked how it works in terms of complex pipelines -- there's no visual editor. I was impressed seeing the graduated blur example,[*] simply because I see this done so badly often and yet right at the top of the page was a nice example.