Ruby is TM's driving force. I don't hack much ruby, when I do I use inf-ruby.el (based on cmuscheme.el by the way - where would ruby be without lisp and scheme ;).

I was assuming TM worked well for ruby, given how ga-ga the ruby crowd is over TM. Does ruby auto-indent and repl integration not work well in TM? Us emacs freaks will need to bring the ruby crowd up to speed with a modern editor.