Harry Potter had a plan. It involved skipping from the Great Hall towards the main artery down to the dungeons. After breakfast, of course. Snape always showed up for breakfast, after all, even if he was often late and frequently only drank a mug of black brew (Harry had once told someone it was grog, not coffee, and then was stuck trying, haltingly, to explain something he had more heard of than seen, until Hermione intervened of course).
So here Harry Potter was, skipping down the halls towards the basement. From behind him, he heard Snape's soft voice, "Skipping in the halls, Potter? Whatever has possessed you to desecrate these hallowed halls of learning with such frivolity?"
Harry Potter spun, looking wildeyed at Snape, and then lowered his eyes, trying to look contrite - and, as usual, failing. "I 'unno."
"Such eloquence informs me not in the slightest." Snape growled, starting to sound more angry (because he always was such an impatient git), "Perhaps you can summon some grandiloquence in detention this evening?"
"Of course, sirrah, of course." Harry Potter said, attempting to summon an ornate bow - which he failed at utterly. From further down the hall (behind Snape, naturally, no one wanted to catch his eye when he was in a mood), there was some tittering and giggling at the utter clumsiness that the Chosen One exhibited when he was not on a broomstick.
Harry Potter knocked on the door to Snape's classroom, having gone there directly after dinner. Snape, obviously, wasn't there yet, as he didn't answer. Harry hoped the man was eating, at least - he looked like a scarecrow in the best of times, and he'd been looking gaunt as of late. Again.
"Door's open." Snape said - his soft voice echoing into Harry's ear*, his long stride taking him down the hallway at a faster, if more controlled, rate than most eleven year olds could run.
Harry Potter entered, standing at a decent facsimile of parade rest - until he heard Snape turn the door handle, at which point he slouched slightly and started to scratch behind his ear.
Snape closed the door, muttering a soft spell to lock it - the whole door glowed yellow, briefly. What was that spell? Harry wondered.
"Speak." Professor Snape said impatiently.
*of course Snape knows ventriloquism. Spy, remember?
[a/n: sorry this is a bit short. ]