So this has been going around for a while, and it still works as of today. Ready to call it a day? Gotta do boring "real life" stuff? Simply go into a gun game match, then walk away from your system. You won't be kicked from inactivity since you don't choose a class during gun game. And since keys are awarded for time played, when you get back you should have a nice handful of keys. Also, need to up your k.d. or do a couple challanges? Go to gun game at night or early morning and kill all the people by punching them to achieve unlimited xp and kd jumps That's the just of it, Goodluck! Source - Om Nomivore