One thing I'd appreciate with these kinds of announcements is a "what is it" paragraph preferably towards the top of the referenced web page. I suppose if I were working in Ruby I'd know what Rubinius is and why I'd care but a list of "what is new" doesn't particularly help me or folk like me.
Here's Wayne Seguin's take on Rubinius (he's the developer behind rvm, and he puts it nicely, I think): Rubinius is a ruby interpreter written in C++ using many advanced techniques and technologies such as LLVM, a "precise, compacting, generational garbage collector", a compatible C extension api to standard MRI Ruby and many other awesome ideas that will give any language nut a huge nerdon. (from http://rvm.beginres…
From http://rubini.us :
Wherever possible Rubinius is written in Ruby. Where not possible (yet), it's C++.
And further down:
The Rubinius bytecode virtual machine is written in C++, incorporating LLVM to compile bytecode to machine code at runtime. The bytecode compiler and vast majority of the core classes are written in pure Ruby.
So, it's the VM that's C++. The bytecode compiler (which is technically what's meant by "interpreter" in this case) is ruby.