Check out the new and improved OAuth admin console, coming at you in version 2.0 (beta available, final release later this week:
The new console is a single-page Sammy.js app that hooks into a lightweight API written using Sinatra, and the whole thing can be mounted into your existing Rails, Sinatra, Padrino or whatever app. To get started run oauth-server setup and follow the instructions.
And yes, that means a Sammy.js plugin, easiest way to add OAuth 2.0 support to your JavaScript app. Also proper support for Rails 3.x, and if you feel the need to practice your OAuth 2.0 skills (or client library), fire up the practice server (oauth-server practice) and point your browser at http://localhost:3000.