You can get 60000 credits in under a hour with this glich. First off you MUST have a ethernet cable, not a wireless a ETHERNETCABLE, you xbox must be fairly clost to you aswell. NExt you must find a daily challange that is something like "get 400 kills in any game type" or anything involving kills and can be done in firefight. Next connect 2nt contrller and sighn it in as a guest the start searching for a game. As soon as the players that have been found show up and you can vote for the map sighn out of the second controller leaving only you in the game. Now pick any game mode, i like rocket fight, and if the challange was get 400 kills you need to get 399 and save and quit. DO the same controller trick then when you get into the game get 1 kill, the challange will say completed and pop up, AS SOON AS YOU SEE IT POP UP unplug your ethernet cable. IT will disconnect you and quickly plug it back it. Press menu button and connect to xbox live. Get another kill and unplug your ethernet. What it is doing is giving your credits for the challange then when you disconnect it sets how many kills you go tfor that challange back to 1 away, do that over and over and you will be higher than you friends in now time hope you guys liked =) +rep maybe?