Steam Gives out Guest Passes
A highly welcome move by Valve is the introduction of “Guest Pass” in Steam, allowing owners of certain Steam games send time-limited demos to their friends. This post on the service’s website states that a beta will be conducted after which the Guest Pass system will be extended to Day of Defeat: Source owners.
No specific titles were mentioned, though Half-Life 2 and other big titles can be taken as staples.
BDGamers 
Hi all!!! Cool site!!!