The example I'm working with specifies the scope in the OAuth request as: scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fuserinfo.email+https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fuserinfo.profile
which decodes into two URIs:
I cannot find documentation covering the complete list of scopes that are available and what information is accessible within each scope - does anyone know if such a thing exists?
What you are looking for is the Google APIs Discovery Service.
A few other interesting resources:
An excellent blog by Nicolas Garnier which describes the important things behind this service.
The Google OAuth2 playground, is another good source of info.
Finally if you're interested in tracking changes to the discovery documents or don't want to read all the docs, there is an interesting online implementation by Gerwin Sturm.