Harry Potter had something to say to Snape, and the hubbub of the room made a decent cover, as most people hadn't deigned to sit (and Snape, while seated, had his back to the wall and was using his sharply angular legs to clear space around him). Harry approached from the side, quietly moving in the holes in the crowd. It was something he'd taken to early in his life, in primary school when drawing notice meant the pain of Dudley's punch. The pace was excruciatingly slow... but it was also nearly unnoticeable. Not that most of his friends were looking, but there was always the chance that Remus Lupin or Moody would look up and see.
By the time Harry had approached to something resembling Snape's side (standing about three feet away - a far, but comfortable distance for talking), the room was getting inordinately crowded.
They both faced the crowd, as was prudent. Harry spoke up, trying (and probably failing) to emulate Snape's liltingly soft voice. "Thank you for the detention, sir."
"Are you trying to insinuate that I'm losing my memory?" Snape spat, "Exactly when was this mythical detention?"
"Why, right now, of course." Harry said, his mouth curving slightly into a shadow of a smile.
"What possible reason did you see to involve me in your lies?" Snape hissed.
"You're the reason I had to lie in the first place." Harry stated baldly.
Snape shot to his feet, the elegantly facade of nonchalance evaporating instantly. "How's that?" Snape's hands had curled into fists, and Harry could see the effort he was putting into not grabbing Harry by the collar and throwing him against the wall.
"Fudge wanted Malfoy and I to support his campaign. The Minister looked like his brief conversation might have lasted days." Potter said, his eyes cold. "Malfoy may still be there, for all I know."
"Very well," Snape said, those black eyes drilling into Harry's green eye (Harry had still not turned to face Snape, maintaining the insouciant pose), "In the future, anything you need my word to back up should be communicated to me as soon as possible." Harry nodded, his eyes discretely on Snape. "At that point, I will decide whether or not I will corroborate your story." Harry's feet shifted uneasily beneath him - he really hadn't asked himself what he'd have done if Snape had just called him a worthless liar. "I will, of course, inform you of this, so that you may prepare accordingly."
"Yes, sir." Harry Potter said crisply.
In a voice that was softer than a whisper, Snape added, "One point to Gryffindor. For cleverness. It would hardly do for you, of all people, to miss the first meeting of the year. People still look to you to set an example, gods know why."
In the great hall, one ruby gem dropped into the bottom of the hourglass. Harry had seen that happen so many times over the course of his schooling, but this one was different. Like a crack in the ground after an earthquake, it just sat there - radiating latent danger. Kind of like Snape himself, if you think about it.
"ORDER!" Dumbledore rumbled.
"Next stop: The Valley of Boredom." Snape drawled softly, carrying his chair back to the table.
[a/n: Anyone figured out why Snape was early?
Fudge really wanted to corner Harry and Malfoy for the rest of the day.
Malfoy, of course, was not pleased about being stuck with Fudge.
Snape is not opposed to using positive reinforcement on Gryffindors, but that requires that he has something to reward.