A pub quiz was a trivia contest conducted in a pub.
To learn why Mary said Toshiko Sato could call her Philoctetes instead of Mary in 2007, she asked Jack Harkness who he was. To divert suspicion, she claimed that it was a question in a pub quiz at the Prince of Tides. (TV: Greeks Bearing Gifts)
While in Cheldon Bonniface in April 2010, Bernice Summerfield, Jason Kane and their wedding party frequented the Black Swan. One night, they even participated in a pub quiz there. (PROSE: Happy Endings)