Needless to say, the post-HBP Snapefic is on indefinite hold. So, I present to you what I've written so far:
Like the tavern itself, there was little about the barman at the Hog's Head that encouraged a second glance. The pub consisted chiefly of one squalid, dimly lit room whose windows and furnishings were overlaid with a thick film of greasy dirt; likewise the man who tended it seemed to be made up of little more than dingy robes, tangled grey hair and grime. And just as the wise customer (assuming, of course, that it could ever be considered wise to enter the Hog's Head in the first place) ought not to look too closely at the glass that held his beer lest he find out more than he really wanted to know, even so there was something about the Hog's Head's proprietor that caused one's gaze to slide away from him almost at once, leaving in the viewer's mind only a vague impression of a skinny, unkempt old man possessed of no notable or attractive qualities whatsoever, and a slight sense of relief for not having scrutinized him more closely.
The barman -- as he was most often called, as few people seemed to know his name -- rarely spoke unless spoken to, and when he did reply it was in the form of a single laconic word or, more often, a grunt. Unlike the Three Broomsticks, where Madam Rosmerta's winsome appearance and manner was one of the place's chief selling points, no one came to the Hog's Head to converse with its proprietor. The only virtues of the Hog's Head, in short, were that the drinks came cheap and nobody asked questions.
As such, it was not surprising that when a cloaked and hooded figure entered the Hog's Head late one July evening, neither the bartender nor any of the other patrons showed the slightest curiosity. In fact, there were already three other customers in the bar similarly attired, so the newcomer did not even stand out amidst the sparse crowd. Dropping a coin indifferently upon the bar and receiving a murky half-pint of Goblin Ale in return, the stranger glided to a table in the pub's back corner and sat down. There he remained, alone and silent, with a pair of thin, sallow, prominent-knuckled hands folded about his glass, until the rest of the pub had all but forgotten his existence.
Some time later the barman came shuffling through with a tray and picked up a few stray glasses, his air of dull disinterest so complete that no one even saw him drop a small, heavily scarred brass key onto the stranger's table. Nor did anyone notice the hooded man's pale fingers loosen their grip on the glass just long enough to palm the key and make it vanish. And when at length the gargoyle's head nailed up behind the bar croaked "Last call!", the few remaining patrons drained their cups and staggered out into the night without ever realizing that the stranger in the back corner was not among them.
The door of the pub thudded shut, bar dropping and bolts grinding home; one by one the sickly-looking lamps went out, and the main room of the Hog's Head was swallowed up in darkness. Only a single wan light remained burning behind the bar, as the barman waved a negligent wand to Summon the remaining glasses and give them a last cursory cleaning. Then this lamp too was extinguished, a door creaked open and shut, and to all appearances the Hog's Head stood empty for the night.
For several more moments the stranger did not move, his head bowed over his untouched drink. Then he slid smoothly out of his chair and wove his way through the shadowy maze of tables to the front of the bar. Crouching, he swept his hands across the floor, heedless of the sticky filth that covered it, until he had found a trapdoor set into the battered boards. One long finger traced the outline of a keyhole; deftly the little brass key was conjured, inserted, turned; and with a harsh whisper of "Lumos," the hooded man swung himself into the newly revealed hole and dropped into the darkness beneath.
By wandlight, it was just possible for the visitor to see that he had landed in a tunnel, lined with ancient stone and winding off in three directions away from the Hog's Head. Another pass of the wand, another murmured command, and the middle path began, very softly, to glow: immediately the stranger slid his wand back into his sleeve and strode down the corridor his spell had indicated. Several paces later, however, the path ended abruptly at a closed door, and this time the cloaked man was obliged to lift his hand and knock.
No sound came from the other side, but a few seconds later the door groaned open and the unkempt figure of the Hog's Head's barman stepped out, a tall gaunt silhouette against the light. There was no expression on his face, nor in his voice as he said gruffly, "Well?"
The other man paused for an instant, then lifted his hands and pulled back his hood. Firelight from the room beyond flickered across his features, revealing the glittering black eyes, hooked nose, and thin, almost bloodless lips of Severus Snape.
"Hmph," grunted the barman, and hit him.
For an old man, he could strike with surprising force. Snape's head snapped back, and he staggered; when he lifted his head again the corner of his mouth was bleeding. In a rough voice he said, "Albus never told you to do that."
The barman shrugged, apparently unfazed by the rebuke. "Not Albus."
"No," said Snape with a bitter edge in his voice, "that, you most certainly are not," and stalked past him into the room beyond.
Not much to it yet, admittedly, but maybe in another few days I'll be feeling better and able to add more...