Steam Guest Passes

Later this week, new menu options will appear within Steam as Valve initiates the closed beta for Guest Passes, a new feature that will allow owners of certain Steam-enabled games (purchased either via Steam or at retail) to send a friend limited-time trials for those games. During the beta period the new menu items will appear on all Steam accounts, though the ability to send the Guest Pass will be inactive. When this closed beta concludes, Valve will extend the Steam Guest Pass Beta to Day of Defeat: Source owners.

As the message notes, this will be a closed beta for starters, but the functionality is on the way! Personally, I think this is far more practical than a free weekend. This way, you can invite a friend to try out a game on your terms.