Beginning on the 19th people will be able to play Futuremarks' Shattered Horizons for free over the Steam service. While this is not the first free weekend hosted by Steam it is the first time that Shattered Horizons has been offered for free.
The even comes on the heels of the launch of a new map pack for the Zero Gravity first person shooter. The map pack is called Moonrise and features four new levels that are free to all players. Futuremark has gone an additional step with their free weekend though; they are also offering Shattered Horizons for 50% off for the duration of the weekend.
This makes getting into some serious DX10 based zero gravity mayhem even easier and more attractive. If you already have a steam account you are all set; if not you can head over to Steampowered.com and get set up.