How to obtain a OpenId Identifier from Google

I don't think commandlinefu supports Google OpenIDs. They need to properly add it with the method shown here. When added, a link is provided that redirects to Google's login page and uses the login process shown here:

since their site lacks this, the method cannot be used.

Support for Google OpenIDs has been requested on their uservoice.

Use the following in the OpenID prompt:

https://www.google.com/accounts/o8/id

It will redirect to Google's auth service and if you are already logged in with your Google account then the login to the site using OpenID should be transparent.