Time travel/body swap

[crideon]

I woke up thinking about a story I read a while back where Colin and Bradley changed places with Merlin and Arthur.  Each pair had to navigate a strange new world and deal with its challenges.

I find that now I'm in the mood for more of that sort of story, where one or both of the canon characters get transported to modern times, or the actors end up in the canon world.  Self recs welcomed, gen or slash = fine with me.

And may I say how much I love this community.  I get so much reading fodder from other peoples' requests. :-)