Some other guy is who your girlfriend is going out with. He is the guy all other guys aspire to be. He is currently in 666 relationships right now, and has had more sex than a porn star caught in a Temporal Infinity Loop created by the USS Enterprise's deflector dish. He is everything that you are not and will never be. * Guy: "*sobs* My girlfriend is cheating on me." * Other guy: "Dude, who is he?" * Guy: "I dunno, Some Other Guy."