Hi!
font-lock doesn't seem to work in ruby buffers.  I've attached the file
ruby-mode.el which is part of the ruby distribution. 
When I open a source file, I see 
  Fontifying f.rb... aborted.aborted.
in the message buffer.  Also, the warning
  (1) (warning/warning) Error caught in `font-lock-pre-idle-hook':
      (malformed-list ?\') 
come up in tons.  I don't know left from right with font-locking, so I
can't figure out the problem to say nothing of its solution (might be
some differences between emacs and xemacs, though).
Any takers?  TIA,
norbert.