Alex English and GBH return with their big electronic-dance-music bash, the Girls & Boys affair, held in Webster Hall’s massive Grand Ballroom. Tonight's party sees Alter Ego, the duo that's spent the last decade creating sometimes-goofy, always-fun techno, laced with electro and pop sensibilities (largely for Playhouse imprint Klang Elektronik), playing live. Hudson Mohawke is young Scotsman Ross Birchard, a creator of some rather amazing near-psychedelic, R&B-derived rhythms that manage to strut and shimmer despite their sometimes glitchy predilections. Disko Dali and the Fixed boys supply able support. Go to gbh.tv to get on the reduced-admission list.