Company of Heroes is a Real Time Strategy game developed by Relic Entertainment; whom are also known for the Dawn of War series.
CoH isn't DoW thankfully, the game features base building and squad control with players being able to build base structures such as barracks and defensive structures such as bunkers and outposts.
The object of multiplayer matches changes depending on the game mode but usually the basics are to capture territories in order to generate resources and increase your population cap with the ultimate goal of destroying the enemy. Maps are split into territories with control points which can be either munitions nodes, fuel nodes or control nodes; munitions nodes and fuel nodes add to the generation of those resources for the team holding the points, while control nodes give victory points (in Victory Point Control gamemode), all nodes add population cap.
Squads and units can be upgraded by spending resources on upgrades for either the squads themselves (such as adding rifles or bazookas to a squad) or global upgrades which apply to all units they are intended to effect (such as ability unlocks).
Company of Heroes starts with 2 focuses on the conflict between the Allies and Axis during WW2; the original game allows you to play as the Americans for the Allies and the German Wehrmacht for the Axis, the first expansion Opposing Fronts unlocks the British for the Allies and the Panzer Elite for the Axis. The second expansion Tales of Valor unlocks some extra units for each faction and allows you to switch between vanilla or the ToV units.
Each individual faction has their own unique strengths, weaknesses, units and ways of upgrading/teching up:
Americans - Versatile basic faction, has decent tanks and infantry, can build defensive buildings such as bunkers and outposts. Upgrades by spending resources to build the next production building and unlock more units.
British - Defensive advanced faction, has few tanks but good infantry, can build a variety of defensive buildings such as machine gun emplacements, anti-tank gun emplacements and mortars. Techs up by building commander units (Lieutenant, Captain, Commander) which then allow the construction of the next production building (which for the British take the form of mobile deployable vehicles), commander units also give bonuses to nearby units.
Wehrmacht - Versatile basic faction, decent tanks and infantry with the ability to build defensive buildings such as bunkers and outposts. Upgrades by spending resources to 'escalate' to the next 'phase of battle' (tech level), which allows building of more production buildings and thus more units.
Panzer Elite - Offensive advanced faction, has only 3 or 4 infantry squads which can then be upgraded by purchasing upgrades from various base buildings, starting infantry act as combined engineers/riflemen. The Panzer Elite has a good selection of tanks, but is unable to build any defensive buildings and has to spend extra resources to research upgrades at production buildings before being able to upgrade units.
There are also commander specialties, which come in three forms and allow the player to customize the way they play. Each faction has its own set of specialties, which usually are split into defensive/support, offensive/infantry and offensive/tank (not all follow this logic), tank specialties give bonuses to your armour and allow you to call in special tanks for example.
A few of us in Pizza play CoH, it was on sale during the Steam sale so perhaps some other people bought it and are looking for people to play with; just PM me or we can add steam/relic names and get some matches going.