Short horror story plots that take place in a bar?

Eh I guess that beats teaching you two dozen words for obscure forms of motor bike.

You could purloin Spider Robinson's tale of an alcoholic vampire who offers patrons free rides home, so he can have his "bloody mary."

I can think of a baker's dozen such bar stories, which usually start with a bar room discussion, which gradually gets a little strange, and then finish with the big reveal that one of the patrons or all the patrons, is or are a werewolf, alien, vampire, worshiper of Cthulu, or ghost. Often the patron is then devoured alive or narrowly escapes to tell the tale. Sometimes he is just spooked and flees into the night. Alternatively, the patron returns to the bar the next day to find the bar, only to have residents insist that no such strange bar exists or that the "tavern burned down fifty years go." Given your Athens setting, you could easily have an older Romanian gentleman telling his life story. You could also have an assortment of stock ghosts such as a dead Lord Byron or a sad victorian era lover searching for her beau.

You could also write a bit of parody, have a little working class bar filled with people griping about their bosses, only this one is filled with hunchbacks named Igor and nervous men named Renfield.

You could also skip the stock horror show characters and write a story where it's gradually made plain that patrons of the bar are leftovers form the old greek myths. Not the Olympians, but the darker tales of goat legged men and followers of Dionysus. The mystery cults.

Which would make good story as well. Put aside supernatural elements and have the bar just be the center of the last Pan or Dionysus cult, making blood sacrifices of hapless tourists and English holiday makers. A drunken, sexualized evening which ends in the guest being torn apart by the frenzied crowd. Our view of the old greeks often has been white washed by the would be vicars who mde them so popular int he 19th century. All white marble, instead of dark mystery. It'd be along the lines of the stock hollywood story where the small town is revealed to be a satanic cult.

a guy inherets an previous domicile from a relative in his will. the guy comes to a decision to stay there, and weird and wonderful issues start to ensue. To make an prolonged tale short, the home is haunted.