Have an OpenID that consists of a group of member OpenIDs. To login as the Group OpenID you need to login with any of the member OpenIDs. This is discussed more by Dmitry Shechtman on his blog.
I find that I already have a couple of OpenIDs without even trying due to AOL giving out OpenIDs. I'd like for all of my OpenIDs to point to one canonical OpenID. It looks like this may already be possible by the OpenID specification.