Courtenay of the caboo.se has put together a solid "sample Rails application" that enables you to get up and running with a new Rails application quickly.

It includes several useful features out of the box:

• views implemented with Yahoo! YUI CSS grids
• timezone support
• basic authorization system with RESTful authentication
• polymorphic image model
• around_filters with scoping
• exception notification

You can learn more about the sample app in Courtenay's first post about it. Even if you don't find the template directly useful, it's worth looking at to see how a proficient Rails developer will begin to construct an application from scratch.

(Update, April 12: Courtenay has released version 3 today!)