Robokassa is payment system, that provides a single simple interface for payment systems popular in Russia. If you have customers in Russia you can use the gem. The first thing about this gem, is that it was oribinally designed for spree commerce. So keep it in mind.

RubiGen - Ruby Generator Framework

A simple to use, yet powerful Ruby framework for building console-based applications.

This is a Ruby API for Fitbit.com, currently scraping, but soon will use the officail API (when released)

Call Lua from Ruby (and Ruby from Lua in Ruby)

ScheduleFu allows scheduling events with dates and times. It includes both the model and view portions of a calendar. It borrow heavily from acts_as_calendar (http://github.com/dball/acts_as_calendar) and calendar_helper (http://github.com/topfunky/calendar_helper).

Integrate SimpleCov results into Atlassian Bamboo CI server

SocialPoster is a gem that allows you easily post to different social networks.

Spree Mail extends Spree by adding a mailing list subscriber model, sign up forms and an admin to send messages.

Spree Redirects adds an interface for redirecting old url's to new ones.

Tiny IRC Bot Frameowkr

Provides term extraction functionality

Port of UEA-Lite Stemmer to Ruby, a conservative stemmer for search and indexing.

Simplied interface to use ruby the libvirt ruby library

whmcs-ruby: Ruby bindings for the WHMCS API

A simple API client for the XBMC Media Center JSON-RPC API

This is taken from XMLCanonicalizer/WSS4R and http://github.com/borisnadion/xml-canonicalizer

A complete Ruby API for handling SMS messages via 4info.com

Act-as-Buddy is a gem to allow any model to implement self relation. For eg: the friendships of a user can be implemented easily by self relation technique of act_as_buddy. Any Model can be buddied or lopped on to itself. Main uses would be for Users create friends etc.. Eg: User has many friends...

You can use active_cart as the basis of a shopping cart system. It's not a shopping cart application - it's a shopping cart framework.