Usually when gamers rap about video games, you wish they just wouldn't. But Dan the Bull is an exception. You'll want to check out his angry opinion on DLC in the video below for his jam called DLC PLC, I promise. Guy's got flow, you must admit.
Of course, if you'd rather listen to "real" rappers rap about games and tech, instead of gamers rapping, there's one cool, innovative source: G4's own regrettably discontinued web series Freestyle 101. Start with the great Del, then spend all day listening to the rest.