Amy and Rory
Amy and Rory were standing in the control room, watching galaxies go by on the screen. The TARDIS was drifting through space without a care in the world, their daughter was somewhere on board with them, and everyone was happy. Suddenly, Rory turned to Amy with a grin on his face.
"Remember that game we used to play when we were little? Not the one where I was the doctor, the other one."
"Tag?"
"Yeah. We used to run all around the town playing that, do you remember?"
"Yeah. What made you mention it now?"
"Well, I was thinking, the TARDIS has lots of corridors that would be perfect for running around…" No sooner had he said that than his wife had yelled "Tag!" touched him, and run away down one of the many corridors. "I will catch you!" he yelled and went charging after her.
For about half an hour, the pair of them ran around the TARDIS, hot on each other's heels. After they had passed the swimming pool for about the fifth time, they heard a faint scream coming from behind them. Rory, who had been being pursued by Amy, turned around and she ran into him. They looked in the direction the sound had come from, looked at each other, said "River!" together, and turned and ran in the direction from whence they had come. There was some more screaming, and some yelling, before they managed to find the right corridor.
They turned into the corridor and slowed down. It was silent. A door about halfway down was ajar, and as they moved cautiously towards the room they could hear heavy breathing coming from within. As they neared the room, they saw there was a red bow-tie hanging on the door, and a fez stopped the door from closing completely. They peered at the sliver of the room they could see. The bed was obscured from view by the door, but they could see a tweed jacket and a pair of female boots lying on the floor and cabinet, as if flung there from across the room. There were two sets of irregular, heavy breathing emanating from within.
The Ponds looked at each other awkwardly, not sure what to do. Amy whispered, "Maybe…we should leave them…alone…" Rory nodded and whispered "Yeeah," in reply, and together they tiptoed away as quietly as possible. When they got to the end of the corridor, Rory said, "You're still in!" and ran off down a perpendicular corridor. Amy ran after him.
When they next saw River and the Doctor, they were all in the control room again, standing around awkwardly. River and the Doctor refused to make eye contact, and the ponds wouldn't look at anybody. They stood there until the Doctor cleared his throat and said, "We could go to the land of coffee shops now, if you like." There was a mutual agreement, and so off to the land of coffee shops they went, spiralling through space and time once more. No one ever mentioned that day again.