>> As a follow-up on the other people mentioning (g)vim: I think it 
>> should be pointed out that you can embed a ruby interpreter in (g)vim 
>> and then program the editor with ruby or run ruby code right from 
>> within vim.
> 
> 
> Directions please. :)

Type :version<cr> or to get some information about the activated 
features. If there is a +ruby somewhere you're fine. (Or type :echo 
has('ruby')<cr>.) If the feature list includes +ruby/dyn the ruby 
interpreter is loaded on demand, which requires a suitable ruby library 
to be installed. On windows, this currently means that msvcrt-ruby18.dll 
has to be around some place in the path. Then check out the help on ruby 
support: :help ruby<cr>

HTH,
Thomas.