Today marks the fourth birthday of GameTap, the popular PC game subscription-download site. To celebrate the site has added a new game to its premimum monthly subscription tier. It's Unreal Tournament III, the 2007 shooter from Epic Games. The game has full 64-bit support enabled for those of you running such an OS on your PC.

But that's not all. GameTap has also enabled 64-bit support for a number of their games that are already on their service. Even better news is that this weekend a good portion of those games can be played for free. Check out the entire list for yourself to see if there's something that interests you:

Project Snowblind (free this weekend)
Hitman: Contracts (free this weekend)
Tomb Raider: Anniversary (free this weekend)
D.N.A. (free this weekend)
Sacred Gold (free this weekend)
Magic Ball 3 (free this weekend)
Hitman: Blood Money (free this weekend)
Unreal Tournament 2004
Beach Life (free this weekend)
Turtix (free this weekend)
Infernal (free this weekend)
Overlord
Hospital Tycoon
Tomb Raider Legend (free this weekend)