What if they incorporate Matt Smith carrying the torch into series 7 of Doctor Who.
Scenario: The Eleventh Doctor is in Cardiff, minding his own business as he waits for the TARDIS to recharge along the rift. Suddenly, somebody hands him the Olympic torch, and, baffled, he just goes for it, because, hey, why not? He runs, and passes it off to the next torchbearer at the checkpoint.
When he gets back to the TARDIS, the Ponds (or Jenna’s character) ask him where he’s been, and he just says…
“I think I’ve just started something that I already finished.”
And they go a few days into the future, when the torch finally reaches London, and flip on the telly to see the “news” scene from near the end of Fear Her, when the Tenth Doctor lights the torch.