Jack shrugs. The Doctor pretty much said it all, after all. Ever since he first left to travel the stars, Jack's been delighted by all three of Clay's options. Maybe this technology isn't the sort of thing he's usually interested in, but that doesn't stop it being fascinating.

And people and cultures? Well. You don't travel with the Doctor if you don't appreciate those.

"Pretty much," he agrees, grinning. "What about you? Got anything particular in mind?"