The Titan Pack, a massive batch of downloadable content, was released for the PC version of multiplayer shooter Unreal Tournament 3 today and to revitalize interest in the game, Steam will let you play UT3 for free all this weekend.

All you need to do to play UT3 for zero dollars is sign up for a free Steam account. In addition, UT3 Black (the bundle with the retail game and the Titan Pack) will be 40% off until March 15th - which means it's $11.99 instead of $19.99. Here's the full list of new content the Titan Pack adds to UT3 (quoted from the product page):

• 16 environments — four Warfare, three vCTF, six Deathmatch, and three CTF maps — that are new to the PC and PS3 versions
• Three bonus pack maps, CTF-Face, CTF-Searchlight and DM-Morbias
• The namesake Titan mutator, which lets players overwhelm opponents as a 15 foot tall titan, or crush them as a 30 foot tall Behemoth
• Greed and Betrayal, two gametypes that breed new-found fervor throughout the competitive UT3 arena
• Two powerful weapons, the Stinger Turret and Eradicator Cannon artillery
• Two valuable deployables, the X-Ray Field and Link Station
• The Slow Field power-up, a portable version of the Slow Field deployable
• Stealthbender, a new vehicle that carries two spidermine trap deployables, one EMP mine, and one each of the new Link Station and X-Ray Field deployables
• Two new characters, Nova and Kana
• 57 awards attainable as Steam Achievements
• Significant AI enhancements, especially in vehicle gametypes; networking performance upgrades; greatly improved menu flow and UI usability; better mod support
• Client-side demo recording, highly improved Server Browser, a new maplist system, plus mid-game mutator and gametype voting functionality for PC

The Titan Pack was set to be released for the PS3 version of UT3 as well but was delayed yesterday. It should arrive in a couple weeks.