What can be done in 15 minutes?
redmine.org is a ticketing system built in rails
heroku.com rails deployment the easy way
tryruby.org the language itself, try the interactive tutorial, for you to make an informed decision.
Everthing you’ve ever tried doing in another language is covered on railscasts.com
checkout a sample of the available screencasts
as you can see the railscasts and a great reason to use ruby.
RefineryCMS: a great prebuilt cms written with rails
Check this video on vimeo for a run down on it.
RadiantCMS: another cms to chose from.
Typo this is one of the projects that has been around the longest.