Crafty lets you create HTML output with pure Ruby.
Create consistent snapshots of all EBS volumes on an Amazon EC2 instance with minimal configuration
Mailifier allows you to display emailaddresses in webpages whilst preventing spambots from harvesting them.
Flipflop lets you declare and manage feature flags in your Rails application.
JRB is a template adapter for Rails. JRB templates are Just Ruby.
Simple, view-based pagination for Rails. Built on top of Active Record 3 awesomeness.
Generate Entity-Relationship Diagrams for Rails applications
Sedna XML database client library for Ruby
Stampede is an extendable and scriptable tool to test and measure (web) server performance.