BOF

from Jargon File (4.4.4, 14 Aug 2003)

BOF
 /B.O.F/, /bof/, n.

   1. [common] Abbreviation for the phrase "Birds Of a Feather" (flocking
   together), an informal discussion group and/or bull session scheduled
   on a conference program. It is not clear where or when this term
   originated, but it is now associated with the USENIX conferences for
   Unix techies and was already established there by 1984. It was used
   earlier than that at DECUS conferences and is reported to have been
   common at SHARE meetings as far back as the early 1960s.

   2. Acronym, "Beginning of File".

from The Free On-line Dictionary of Computing (8 July 2008)

BOF

   /B-O-F/ or /bof/ 1. {Birds Of a Feather}.

   2. Boring Old Fart.

   [{Jargon File}]

from V.E.R.A. -- Virtual Entity of Relevant Acronyms (June 2006)

BOF
       Birds Of a Feather (Usenix)