BlankSlate from Builder. This is supposed to be a separate gem, but I can't find it anywhere.
A block explorer for Blockstack
Duplicity Chef Cookbook
compass rails integration
A DataMapper adapter for redis
Show multiple, overlapping events across calendar days and rows. Rails plugin.
Helps with serving font assets with Rails 3.1
Full-sized drag & drop event calendar (jQuery plugin)
Google Checkout library for Ruby
Jekyll is a blog-aware, static site generator in Ruby
pushState + ajax = pjax
Liquid markup language. Safe, customer facing template language for flexible web apps.
Ruby Interface to Maxmind's minFraud service
Easy tools for adding OAuth2 to Ruby web apps
ROXML is a module for binding Ruby classes to XML. It supports custom mapping and bidirectional marshalling between Ruby and XML using annotation-style class methods, via Nokogiri or LibXML.
User agent string parser for Ruby
A viral landing page for startups to use
Plug and play websocket support for ruby on rails.