The Room
Disclaimer: Do I REALLY have to say it? Like, no duh I don't own H.P. If I did, I sure wouldn't be righting a little dinky story on fan fiction.
Ron put Harry in a room that was completely round. There were no corners. Even the ceiling was curved. Where this room was in the castle, I don't know. It was specifically made for this joke. Maybe it was in the room of requirement. But, the point is, it was there.
Harry looked around. 'Why am I here?'
'I want to confuse you. Okay, now, go sit in the corner.' Then, Ron closed the door. He laughed. 'Perrrrrrrrrfect.' Then Hermione looked at him weird.
'Have you been sniffing cat nip again?' Ron looked to the floor, ashamed. 'I told you, Mrs. Norris is a bad influence. You have to stop hanging out with her.'
About an hour later, Harry came up to Ron. 'I thought I told you to go sit in the corner.'
Harry looked blankly at his friend. 'I did.'