Is there a way to query for action instances?

In the beta of the open graph, I see开发者_如何学Python how you can access action instances if you know their IDs:

http://developers.facebook.com/docs/beta/opengraph/actions/

How do you find the action instances in the first place? I don't see any new collections in the graph api that associate a user with their action instances.

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It looks like the action collections do exist with the application namespace prefixed. E.g. an app that has a namespace of "example_org" and an action named "read" would be accessed at:

https://graph.facebook.com/me/example_org:read

I haven't figured out any way to query for which action collections exist. I tried adding ?metadata=1, but that didn't show them.