First, please read the Advanced Rails Caching.. On the Edge for a primer on ESI, caching, and fragments. To get started developing with ESI, I'm going to walk through a simple tutorial building an ESI enabled Rails application. Get Mongrel-ESI Find the latest mongrel ESI here: http://code.google.com/p/mongrel-esi/downloads/list wget http://mongrel-esi.googlecode.com/files/mongrel-esi-0.0.5.gem (Do