Another publisher signed a deal with GOG to sell and distribute games, DRM-free. To launch their partnership with Warner Bros. Interactive Entertainment, six games have been added and five of them are on sale. LEGO Batman (50%-off), the two LEGO Harry Potter games (each 60%-off), F.E.A.R. Platinum (50%-off), and Bastion (60%-off) will be at their reduced prices all week.
The sixth title comes from their acquisition of Midway Games and is actually a three-game combo: Mortal Kombat 1+2+3. One person in the comments said that they are DOS-based versions and controller support might be a problem (although JoyToKey should solve that problem nicely – especially for a fighting game without analog controls). The first two games only support single PC multiplayer, although Mortal Kombat 3 allows LAN. Of course, LAN support should be easily extended to online multiplayer with people that you know online via VPN software, but I have not tried it myself and lag could be a problem.
All six titles are DRM-free, because it's GOG and that's how they roll.