I just ran across this on the net(if your pc is good enough), its the F.E.A.R. multiplayer only game, you can play with peeps who have the full version online and its free!.
http://www.fileplanet.com/166516/160...E.A.R.-Combat-[FREE-Multiplayer]
I also found this Battlefield 2 type game that is also free, good looking screenshots, im downloading it now!
http://warrock.net/screenshots.php
Also this one looks cool and is free
http://www.cubeengine.com/