MagLev is a Ruby VM in the works by Gemstone that is targeted for a first release around September of 2008. I am really excited about this development. The VM will hook up to the caches and persistent store that Gemstone provides.
Avi Bryant gave a nice demo of 100 days of work on the VM. It does simple things in the typical Gemstone distributed fashion. Talking with some Gemstone folks afterward, I found out that in 100 days they have implemented about 20% or 30% of the Core library. In the MagLev talk they mentioned that they are effectively (and impressively) running about 38 of the rubyspecs defined by the Rubinius team.
Great stuff.