Heroes of Newerth, a popular cross platform MOBA (Multiplayer Online Battle Arena) game is free-to-play now.
All of HoN heroes are free for everyone, no conditions attached. Excerpts from announcement:
We agree with the community that HoN is best played with a full hero pool available to all players and that both the new and the longtime, dedicated players alike can benefit from the change. We want players to have the freedom to invite their friends and to recommend heroes based on playstyle and not a free hero pool. Players will no longer be limited by which heroes they can afford, so when a line-up calls for a certain hero, you can answer the call and focus on what's important in each game of HoN.
This change is equally important in our mission to revitalize the myriad of game modes in HoN. HoN offers so many other fun twists, options, and strategies outside of All Pick that any passionate fan can attest to. We recognize this and don't want players to be turned away from these modes due to restriction. With all heroes and game modes, players will have the complete HoN experience at their disposal.
Those who already paid for HoN, will get some goodies and refund, check out their announcement here.
If you never tried HoN, I suggest you give it a shot as it is one of the most addictive multiplayer games available on Linux. Check out a video: