Today I'm giving a presentation at RailsConf called "Service Oriented Authentication". Here are links to the example repos on GitHub, the deployed demos on Heroku, and my slides.

Repos

https://github.com/jagthedrummer/so_auth_provider

https://github.com/jagthedrummer/so_auth

https://github.com/jagthedrummer/so_auth_client

Demos

http://so-auth-provider.octolabs.com/

http://so-auth-client.octolabs.com/

Slides

http://jagthedrummer.github.io/service_oriented_authentication/