Valve will start offering user created mods for download on digital distribution platform Steam this week, beginning with five new titles based on Valve’s own Half-Life 2. The five fan-created mods include Age of Chivalry, D.I.P.R.I.P., Insurgency, Synergy, and Zombie Panic. Existing owners of any game using Valve’s Source engine will be able to download and play any of the mods for free. All of the mods use the Steamworks toolset, which provides stat tracking and full integration with the Steam community. Once installed, the mods will appear in the “My Games” list like any other retail title, and will also receive the same automatic updates when available. "We're excited to see mod developers get wider recognition for the hard work they have done, and we hope to support more mod teams in the future," says an official statement on the Steam website.