Sometimes to best way to get up to speed with a new technology is learning by example. I have compiled a list of fully featured, production ready example applications that I consider to be of very decent quality.
Most are RESTful and all have good-great test coverage. I listed components like the authentication, templating, and testing frameworks they employ – perhaps useful if you are looking for examples of say cucumber stories, or maybe how to use haml markup. Also listed are some of the gems and plugins they leverage which I think are either useful or popular and worth checking out if you are not already familiar with them.
If you know of other quality apps I have missed just let me know in the comments section and I will add them. So in no particular order here they are – Enjoy!

Homepage: http://railscasts.com/
Github: http://github.com/ryanb/railscasts
You’ve probably seen his excellent video tutorials, but did you know Ryan Bates also gives away the code that powers his site?
Plugins: redcloth, acts-as-list, will_paginate, whenever
Templates: ERB
Testing: RSpec(controllers, helpers, models)
Search: ThinkingSphinx

Homepage: http://gemcutter.org/
Github: http://github.com/qrush/gemcutter
“Awesome gem hosting”. Good source of cucumber story examples. Also a few Rack examples, including middleware that uses Sinatra to serve files from Amazon’s S3 service. Also some memcache action going on, and some delayed_jobs.
Authentication: clearance
Plugins: pacecar, will_paginate, high_voltage, jrails
Templates: ERB, also uses the 960.gs grid framework
Testing: test unit(functional, unit), Factory Girl, shoulda, cucumber
Search: named_scopes

Homepage: http://www.spot.us/
Github: http://github.com/spot-us/spot-us
Crowdsourcing and Crowdfunding local news stories.
Authentication: restful-authentication
E-Commerce: active_merchant, ssl_requirement
Plugins: acts_as_state_machine(aasm), fastercsv, attribute_fu, paperclip, subdomain_fu
Templates: haml (no sass), compass
Testing: RSpec(models, views, controllers, helpers), Factory Girl

Homepage: http://spreecommerce.com/
Github: http://github.com/railsdog/spree
An excellent base to build ecommerce sites from.
Authentication: authlogic
E-Commerce: active_merchant, ssl_requirement
Plugins: pluginaweek-state_machine, will_paginate, whenever, chronic, acts-as-list, attribute_fu, awesome_nested_set, paperclip
Templating: haml, compass, sass
Testing: RSpec(controllers, models), test unit(functional, unit)

Homepage: http://bostonrb.org/
Github: http://github.com/bostonrb/bostonrb
This is a pretty cutting edge rails app. Follows ThoughtBot’s best practices.
Authentication: clearance
Plugins: inherited_resources, acts_as_versioned, autochronic, geokit, jrails
Templating: haml, sass
Testing: mocha, shoulda, cucumber, Factory Girl, webrat, fakeweb

Homepage: http://www.railsdevelopment.com/
Github: http://github.com/engineyard/rails_dev_directory
Here is a fresh new app just released from the guys at EngineYard. An web directory of professional Rails development firms. Good example for dealing with internationalization(I18N) and localization(L10n). Also many cucumber features.
Authentication: authlogic
Authorization: can_has
Plugins: acts_as_state_machine(aasm), acts-as-list, paperclip, recaptcha, redcloth, shortcode_url, ssl_requirement, will_paginate, xss_terminate, jrails
Search: ThinkingSphinx
Testing: RSpec(controllers, helpers, models), cucumber, Factory Girl

Homepage: http://dogfood.insoshi.com/
Github: http://github.com/insoshi/insoshi
An OpenSource social network platform in Rails
Authentication: restful-authentication, open_id_authentication
Plugins: acts-as-list, annotate_models, attachment_fu, jrails
Search: ultrasphinx
Testing: RSpec(controllers, helpers, models, views)
Bucketwise
Homepage: http://wiki.github.com/jamis/bucketwise
Github: http://github.com/jamis/bucketwise
A simple web based personal finance application. A pretty straight forward application that doesn’t leverage many plugins.
Testing: test unit(unit, functional)
Fat Free CRM
Homepage: http://fatfreecrm.com/
Github: http://github.com/michaeldv/fat_free_crm
Fat Free CRM is an open source Ruby on Rails-based customer relationship management platform. Out of the box it features group collaboration, campaign and lead management, contact lists, and opportunity tracking.
Authentication: authlogic
Plugins: acts_as_commentable, advanced_errors, annotate_models, paperclip, will_paginate
Search: simple_column_search
Templating: haml, sass
Testing: RSpec(controllers, helpers, models, routing, views), faker, Factory Girl

October 14th, 2009 at 2:54 pm
Good list! Also a bunch more listed at http://opensourcerails.com
October 14th, 2009 at 8:22 pm
Great list! Thanks for taking the time to assemble and share this. I somehow didn’t know that spree existed!
October 14th, 2009 at 11:34 pm
Hello, I suggest adding http://www.enginey.com/ as well. http://www.rubymi.org is live project based on http://www.enginey.com an open source social networking project with excellent features
October 15th, 2009 at 1:46 am
Great list of resources. I’m slowly starting to gain interest and study about Ruby and the Rails Framework, and so far, it’s very attractive. These will help me in the learning process. Thanks!
October 15th, 2009 at 6:21 am
Whow! Very good initiative and very insightful. Thank you very much. It is exactly what I need to get started.
October 15th, 2009 at 6:27 am
Gemcutter.org is another great one.
Source available on Github http://github.com/qrush/gemcutter
October 15th, 2009 at 8:29 am
Great resource. I was glad to find insoshi as a viable alternative to tog. Thanks!
October 15th, 2009 at 10:58 am
Great example Neil! I added it to my list.
October 17th, 2009 at 3:07 am
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October 20th, 2009 at 7:25 pm
[...] Jetpack Flight Log » High Quality Ruby on Rails Example Applications This was written by Wayne. Posted on Tuesday, October 20, 2009, at 2:55 pm. Filed under [...]
December 20th, 2009 at 8:22 pm
How about Community Engine – http://www.communityengine.org/?
January 3rd, 2010 at 7:00 pm
[...] This list is still (by far) the best resource I have found for identifying new technology avenues to pursue. [...]
February 5th, 2010 at 2:02 am
nice , very helpfull example, i would lyk to use it