Cb Gb's & O.m.f.u.g. ?

Okay, while shopping I saw this shirt that said " CB’ GB’s & O.M.F.U.G., Home of Underground Rock"

I know what CB GB’s is, its that Bar in New York, but What does the O.M.F.U.G. mean/standfor?

Actually , what does the CBGB Mean/ Stand for?

How’s this?

From www.cbgb.com

Haj

Thank you. for some strange reason that was eating at me.