BYOB is an acronym for Bring Your Own Beer. Commonly used to also mean Bring your own Beef at a Barbecue. In certain regions, including Calgary, Alberta, Canada it's known during the days of the Calgary Exhibition and Stampede to mean Bring Your Own Both (Both being Beer and Beef - the Stampede is a 10 day rodeo). Also Bring Your Own Bud, is common. Street slang in Calgary during Stampede has also adapted this to mean "Bring Your Own Breasts"(for the famous Cowboys Nightclub infamous for paying… (More on Byob)