Hi,
in the parrot mailing list I came across this site
http://homepages.ulb.ac.be/~arigo/psyco/
This is describing some technics used to greatly
improve the execution speed of python, considering
how much python and ruby have in common, I believe
the same technics might be used in ruby for some
great gains.
I hope you find this as interesting as I did.
Benoit