The weird and slightly awesome part about this plot point is that we both could be right. Bran could be the source of every god, every vision, etc. etc.
Bran playing with the past and attempting to communicate is a little more fleshed out in the books. IIRC, he does it with a younger Ned (just like in the show, except completely different context) and Jon Snow (only noticed in hindsight) and one more I can't really remember.