B.Y.O.B. is an acronym for Bring Your Own Beer. Basically what the nude clubs in Vegas used to allow you to do. Las Vegas has currently banned B.Y.O.B.

B.Y.O.B. is an acronym for "bring your own bottle", "bring your own beer" or "bring your own booze". The acronym was first recorded in the 1800s, and is usually used to indicate that the host of a party or social gathering will not be providing alcoholic beverages, but that guests are welcome to bring their own if they choose to do so.