Plugins - Versioned URLs
Add to favoritesMakes it easy to improve the cache-efficiency of a Rails website, completely eliminating repeat HTTP requests for things like javascript files and stylesheets until they actually change.
http://blog.dannyburkes.com/2006/11/2/versioned-urls-for-rails
http://svn.lingr.com/plugins/versioned_urls
Misc. Enhancements
