Weapon annouced for Half-Life 2 that can attract or repel some objects. Assuming the physics engine is good, this will offer the possibility of much mayhem and carnage. A preveiw mentions using this weapon to send tombstones hurtling into zombies, picking up a dune buggy and using it as a battering ram, and picking up, well, barrels. It is unknown whether the weapon can be used on enemies or other players in multiplayer. Presumably, attraction will be on Primary Fire and Repulsion will be on secondary fire (or vice versa). Done right (and how could Valve get it wrong?), this is going to be as revolutionary as the first FPS sniper rifle.
On May 17th, 2004, the Manipulator had its public debut-- albeit in 2D form. Codename Gordon (formally Half-Life 2D) has a manipulator with limited functionality: you can attract objects and then shoot them at enemies. From what little I've played it is, indeed, great fun.