Saffron is a collection of sass mixins and helpers that make adding CSS3 animations and transitions much simpler. Just include a mixin in your sass declaration, then set any configuration using variables and mixin parameters.

Automatically combine media queries

Map helper functions for Sass 3.3 Maps including get-deep and set/set-deep

A web interface for Sensu, a monitoring framework that aims to be simple, malleable, and scalable.

SproutCore is a platform for building native look-and-feel applications on the web. This Ruby library includes a copy of the SproutCore JavaScript framework as well as a Ruby-based build system called Abbot.

A framework for Compass that provides mixins for common CSS patterns to minimize the amount of CSS writing we have to do and gives our stylesheets more meaning.

A Compass extension for Style Prototype dependencies

A long description of this awesome compass extension

Add web components to the Rails asset pipeline

Faster implementation of Haml template language.

Simple item quantity queries mixins for Sass

A collection of web filters for rake-pipeline

Use this if you want to move to the new Resque Web plugin architecture for Resque Scheduler via theresque-web gem, rather than the Sinatra-based approach that is bundled with Resque 1.x

Sassifaction Mixin Library

Spar uses Rack and Sprockets to provide an asset development environment very similar to the asset pipeline found in Rails. It also has built in deployment tasks for deploying your entire site to AWS S3 and Cloudfront.

webgen is used to generate static websites from templates and content files (which can be written in a markup language). It can generate dynamic content like menus on the fly and comes with many powerful extensions.

An UI library for WeChat, includes widgets/modules in mobile web app.

Bemify is a set of mixins to help you write well-structured, component-based modular SCSS source using a BEM-style syntax.

Helpers, Sass mixins and JS shortcuts from Evil Martians

This gem provides jquery-cookie assets for your Rails 3 application.