Books, too. Love this.
I remember back in the days of Usenet, there was a long, meaty, nerdtastic discussion of all the various braided timelines of Back to the Future. Like, for example, what happened to the Marty who grew up with the well-adjusted family in the timeline that sprang into being at the end of BttFI? Did he connect with Doc Brown, given that he already had a good father at home?