rhtml-mode is part of the original Rinari project. It allows editing of rhtml projects without having to use the often flaky MMM-Mode http://www.emacswiki.org/cgi-bin/wiki/MultipleModes. rhtml-mode is presented here as an alternate option to nxhtml-mode which doesn't work for many people.
To use rhtml-mode for editing rhtml files, download the rhtml directory from http://github.com/eschulte/rhtml/tree/master and place it in your elisp directory, then include the following in you emacs .init file
;;; rhtml-mode (add-to-list 'load-path "~/path/to/your/elisp/rhtml") (require 'rhtml-mode) (add-hook 'rhtml-mode-hook (lambda () (rinari-launch)))