Infinity Ward has finally completed work on Call of Duty multiplayer mode Headquarters (HQ), which is delivered in this week's 1.2 patch along with various tweaks and fixes - like the option to balance teams forcefully online.
On the page, HQ mode bears a striking resemblance to Unreal Tournament's Assault mode, but the World War II setting should give it its own feel. The idea, as you've probably guessed, is for one team to hold onto a specific location as an opposing squad attempts to assault and overrun it.
HQ mode joins the existing blend of Allies vs. Axis modes - Deathmatch, Team Deathmatch, Retrieval (capture and hold crucial documents in a team safe), Behind Enemy Lines (outnumbered allies have to survive against overwhelming odds) and Search and Destroy (one team destroys objectives while the other defends) - which were bundled with the game upon release.
To take advantage, all you have to do is download the new 1.2 patch, which isn't really massively big either. You can grab it from FilePlanet, 3D Downloads or anywhere else that takes your fancy, and it weighs in at just 3.6MB.
The larger file that you may have seen knocking about is in fact the complete Linux server package, which is more like 160MB. However if you're an existing COD server admin, you're more likely to want this smaller 1.8MB update.