Source Mods Now Available via Steam

Five mods now available via Steam free of charge for owners of any Source-based game
Valve today announced that five Source mods are now available via Steam, free of charge for owners of any Source-based game. To celebrate the launch of mods, Valve is offering Half-Life 2: Episode One for just $4.99. The list of released mods include Age of Chivalry, D.I.P.R.I.P., Insurgency, Synergy and Zombie Panic.