Here is something for our Doom and Quake fans. Bethesda has released both Quake 4 and Doom 3: BFG Edition on GOG as DRM-free titles. In order to celebrate this, Bethesda is offering both titles with a 75% discount.
As such, PC gamers can get Doom 3: BFG Edition for €4.99 and Quake 4 for €3.79. Bethesda is also offering a pack that contain all of the Quake.
On the other hand, DOOM 3 BFG Edition includes DOOM, DOOM II, DOOM 3, and DOOM 3: Resurrection of Evil, and The Lost Mission (though its mod support is not as great as the one for the original Doom 3 game).
Have fun everyone!