In last year's "Who's On First" blogAthon, I wrote about Clara Oswald's fascination with Roman Emperor Marcus Aurelius.
At the time, I thought it was too late for the series to go on such a journey via the TARDIS and now it officially has as the Doctor and Clara have parted ways.
But it's never too late in fan fiction!
At the end of the "Hell-Bent" episode, Clara and Ashildr/Me took off on their own adventures in Space and Time in a stolen TARDIS that is now stuck looking like a rock n roll cafe.
I think it would be cool if they found themselves back in Rome after Marcus Aurelius became the Emperor in 161 BC. I'm sure there must be some sort of trivial tidbit about his reign that could be the inspiration for one of their first escapades.