Quoted from TheNoTrashCougar:Earthshaker Aftershock. 1 of 1.
--Scott
I was going to say Road Kings 2.0: 1 of 2, but you beat me.
Come to think of it: the rarest pins I've played are mostly (/all?) custom games (Matrix, just a few, but also some 'only one made' games, just like your Earthshaker Aftershock edition).