the easiest way is doing private match or playing offline.this is the easiest game to level up on since there is a lot of challenges
EDIT (by a different person): by going into private matches you can play with your friends etc but you don't get any exp for your online acc and going into split screen or offline you will rank up your offline acc not your online acc
Chat with our AI personalities
Play online
If you are talking about Modern Warfare 3, the answer is no. you rank up until you can create a clan tag, find some friends with one and ask to join, or create your own... Its completely free!
No. Almost. General Shepard beats him up pretty bad and stabs him with a knife, but he dies in modern warfare 3. WHY DOSE HE NEED TO DIE?! WAWAWAWAWAWA!
The player cannot put their hands up in Modern Warfare 2 and even if they could could the enemy may still kill the player anyway. Only Non-Playable Characters at scripted events can put their hands up.
You unlock it by leveling up to Prestige Lvl. 3.