I have created a silver account, and the GT is: MLG GameFinder
You can send a friend request to this account if you are serious about practicing and getting better at MLG gametypes. Once you are on the list, you will get plenty of invites to MLG custom games once the list fills up. You don't have to be a great player to be on the list, but you do have to have a willingness to improve. It is also recommended that you have a mic so you can callout. If you find someone on the list who doesn't know all of the callouts, everyone be nice and help them out. Remember, this is to help people improve. Thanks guys.