The Four Doctors.

Audio  Really good fun and best experienced without foreknowledge so stop reading now if you haven't heard it. Released as a Big Finish subscriber special, this is an interesting take on the multi-Doctor story, as a wayward Dalek collaborator, Colonel Ulrik, finds himself buffeted through time meeting the Doctor's Fifth, Sixth, Seventh and Eighth incarnations.  The narrative partly feels like a way of promoting some of Big Finish's best work, the celebrity historical as Seventh meets Faraday, the war zone tragedy with the Sixth Doctor and a Fifth Doctor comedy of manners.  The Eighth Doctor acts as a kind of temporal shepherd, utilising his memories of all these incidents to help shift Ulrik from one end of his time loop the next.  Mainly a prose writer on Who, notably as co-writer of The Ancestor Cell, Peter Anghelides hasn't written many audios for Big Finish, but this sounds like the work of a veteran who has a real understanding of their potential with nested flashbacks, recreation of events through alternative points of view and understanding of the various incarnations, especially Eighth who immediately sounds in-character.  Timeline talk: Released in December 2010 slap bang in the middle of the With Lucie era, Eighth nevertheless sounds much younger than even the Charley years, so I'm putting it after Shada but before Benny's Story here.