This is just a testing version, but Valve is moving very fast with the development
Dota 2, Valve's own take on the famous Dota mode for Warcraft 3, is now available for the Linux platform.Beside the official support for the Linux platform, Valve also released a generous patch for this free to play title.
Highlights of the latest Dota 2 update:
• Official support has been added for the Linux platform;
• A match making option has been added to opt out the Limited Hero mode;
• The Play Tab will now remember your previous selection;
• Various progression bugs have been fixed in Mechanics II;
• Solo Championship Voting has been added.
Minimum Linux System Requirements: Ubuntu 12.04, Dual Core from Intel or AMD at 2.8 GHz, 4GB RAM, Nvidia GeForce 8600/9600GT, ATI/AMD Radeaon HD2600/3600 (Graphic Drivers: Nvidia 310, AMD 12.11), OpenGL 2.1, 4GB Hard Drive Space, OpenAL Compatible Sound Card.
More details about the free-to-play Dota 2 update can be found on the Steam website. If you want to test Dota 2 you will have to download and play the “Testing” version.