opened its OAuth 2.0 playground to developers last November with support for Google properties and non-Google APIs with support for OAuth 2.0 draft 10. Since then, the company has added a number of new toys to the OAuth Playground, including support for testing client-side apps, in addition to testing Web-based applications.Google
In case you missed it the first time around, the OAuth Playground is a Google-sponsored site that allows developers to work with the OAuth 2 protocol.
Since the release, Google has added support for the client-side flow, which allows developers to test out client applications using the playground. (See also, Facebook's developer docs on client-side flow.)
They've also added support for newer OAuth 2.0 drafts. This gives developers access to drafts up to the March 8th draft (25). Since the Internet does not move at a uniform pace, developers still have access to earlier drafts, as well.
Spending a long time working with an application? The playground now has support for auto-refreshing access tokens – so you don't have to worry about timeouts.
The playground can be used for any OAuth apps, not just Google's services. However, if you're working with applications specific to Google services, you'll now find support for two parameters (access_type, approval_prompt) that are Google-specific. The playground also has support now for Google's API discovery service.
Whether you're working with Google services or just testing applications that need to use OAuth in general, the playground should be an excellent resource.