The Hog's Head

sign: a wild boar's severed head leaking blood onto the white cloth around it
barman: grumpy-looking old man with a great deal of long grey hair and beard, who looked vaguely familiar to Harry (OP16)
A small inn in Hogsmeade, on a side street off the main street, much dirtier (and attracting a more, er, interesting, clientele) than the Three Broomsticks. The bar consists of a single small, dirty room smelling strongly of something that might be goats; while students are permitted to go in, they're advised to bring their own glasses. It's something of a fashion to hide one's face in the Hog's Head, by wearing a hood or veil; Hagrid once won a dragon egg from a hooded stranger in a card game there and shrugged it off, saying that "yeh get a lot o' funny folk in the Hog's Head." (PS16, OP16). Sites of Historical Sorcery mentions that 'the inn' was the headquarters of the 1612 goblin rebellion (PA5), so more secret passages that MWPP didn't find might possibly be associated with it.