Dark Powers (DP) is a teamplay modification for Half-life 2 Deathmatch (HL2DM). DP adds a layer of strategic area control gameplay on top of the standard HL2DM team play. Spawn points are captured by overloading combine consoles with dark energy pellets AKA combine balls. Spawns can also have attached devices to help their teams, such as weapons and health dispensers.
Grab combine energy balls from a reactor, power up a console and unlock extra spawns (and in the example an Armory) for your team.
Powering up consoles with combine balls is key to the additional gameplay in DP.
The panel that allows player to select which spawn they want to power capture all key-presses ATM, so I can't screenshot it for you just yet.