Here is an interesing spinoff of the Black Side of the King's Gambit that was played by an Under 1600 USCF rated chess player in the November 2008 National Chess Congress at Philadelphia , PA inside the Sherton Hotel located at 17th and Race Streets.
Black won this game after White resigned. The analysis is from Chess Master 10th Edition using game analysis time of 20 seconds per move.
Analysis by Chess Master 10th Edition 20 seconds per move
Chess Master 10th Ed agrees with Black's Ninth move
9...c5 10.c3 Qb6 11.Qb3 Qxb3 12.axb3 Nc6 13.O-O cxd4 14.cxd4 O-O
this may have a prepared variation on Black's ninth move because
normal continuation is Bg5 for Black