Possibly moronic Ruby question

[Lee Higginson]

So... out of curiosity I followed the link on Hans email signature
http://hans.fugal.net  because I admire a lot of you guys for your
geekness..  That got me looking at Neelix, the recipe management program so
I thought I would try and run it because my wife has expressed interest in a
program like that.  An hour and a half later, I still don't know what I'm
doing so here's my question to the geek gods.  Since Ruby is an interpreted
language, where do I get the "runtime environment" as I would assume there
would be some kind of thing like that.  I'm trying to run it under WinXP
and/or CentOS 4 but I can only find documentation on programming with Ruby.
Can anyone point me in the right direction?
 
Thanks, 
 
Lee