I've been working with Ruby between 1-2 months and I still have plenty too learn. However, for most programming applications, one simply needs to understand the basics - comments, strings, arrays, variables, methods, objects ect... You can grab these easily enough from online tutorials or querying stack overflow (Ruby lacks support for 2-D arrays, you must build an array of arrays T_T, you should also avoid it if you're planning on developing on Windows or deploying to a Windows Server as I've been told that such an action will only end in tears. Still if you MUST use SQL, I've played with Tiny TDS a little bit).
The cool part about rails, however, are the erb files - which makes dynamic html programming awesome.
For instance, you can do something awesome like this if you had a collection of countries with different names and country colors.
<% for country in countries %>
<p span="color: <%=country.color%>;"><%= "Hello, " + country.name %></p>
Likewise, you can create the equivalent to master pages under the layout section and pass ruby variables from ruby code from the controller - which is nifty to call classes from ect. The annoying part is adding new pages, as you must add a method to the controller named after the view, an html.erb file to the view and then you have to tie it together by adding the path to the html.erb file to your routes.rb file under environment if I remember correctly. Loads of fun stuff.
Of course, if you're looking for an MVC Framework to work with on Java, you might consider playing with the 'Play' Framework. I've been eyeing it as of late and I'm tempted to download it and give it a run myself as it look rather fun, but utilizes scala files instead of erb files.http://www.playframework.com/