Prawn Rails provides a PDF view engine for Rails 3 using the Prawn library. It aims to provide as thin a wrapper around Prawn as possible, while providing Rails integration your used to with other view engines. To get a basic idea of how to use Prawn Rails, have a look at the demos below.
The source for this app can be found at https://github.com/whoops/prawn_rails_demo
Accessing Instance Variables
Overriding the Rendering Class