A sampling of the multiplayer goodness that Battlefield 3 is promising to bring in full October 25 is now available for the PC, PS3 and Xbox 360. Download it here. (You’ll have to log-in to EA’s Origin or create an account.) Expect busy servers, but once you finish the 1.3 GB download for Xbox 360 (PC version a modest 48 MB), you’ll be plucked into the “Operation Metro” map in Rush Mode, which forces one team to protect its assets while the other squad looks to blow ‘em sky high. If you’re one of those longtime Call of Duty fans and you’re thinking about making the switch this year to EA’s military shooter, act quick on this free sample: The beta runs out October 10.