via Aidan Finn’s blog :

widgEditor is a small simple lightweight editor. It provided basic rich functions such as bold, italics, links, lists, images and headings. Rails integration:

• Download widgEditor and uncompress
• Copy the widgEditor.js file into …/public/javascripts folder
• Copy the widgEditor.css file into …/public/stylesheets folder
• Copy all the images from the widgEditor distribution …/public/images folder
• Include the javascript and css files in your layout file
• Give any text field you want to be an editor field a class of ”widgEditor”

<%= stylesheet_link_tag 'widgEditor' %>
<%= javascript_include_tag "widgEditor" %>
<%= text_area 'node', 'content', :cols => "50", 
    :rows=>"3", :class=>"widgEditor" %>