recently I have gotten syntax coloring working and a GUI frontend. Have a look at the screenshots they are ok.
http://aeditor.rubyforge.org/wiki/wiki.pl?MainThemes

editor depends on 2 packages:

dependency#1, iterator:
http://rubyforge.org/frs/download.php/703/iterator-0.8.tar.gz

dependency#2, fxruby
http://fxruby.sourceforge.net/

aeditor itself
http://rubyforge.org/frs/download.php/921/aeditor-1.0.tar.gz

beware: there are font problems on Windows which results in segfaults. Please submit patches if you know how to fix.

--
Simon Strandgaard