If I see myselves at different points of time as being in collusion as to how to make all of us better off, which has been a viewpoint I've seen taken recently, then there is some agreement between a set of sufficiently-similar agents.

If this is too easy, a way to make it more fun is to do the same thing but with parts of you and coalitions of parts of you, gene/meme-eye view of evolution style. Thinking about whether there's an important metaphysical or decision theoretic sense in which an algorithm is 'yours' or 'mine' from this perspective, while seeing if it continues to add up to normality, can lead to more fun still. And if that's still not fun enough you can get really good at the kinds of meditation that supposedly let you intuitively grok all of this nonsense and notice the subtleties from the inside! Maybe. :D