Beginning this Thursday, April 8, gamers around the world can play Call of Duty: Modern Warfare 2 multiplayer free of charge during a special Free Weekend promotion on Steam. The definitive online experience, Modern Warfare 2 returns with a host of new perks and enhancements. Those who wish to enjoy every moment of the Modern Warfare 2 multiplayer Free Weekend may pre-load Modern Warfare 2 multiplayer now . There is no obligation to participate.