Quake 4 has been the only PC game in id Software's Quake series of first person shooter that has been unavailable to download and purchase (legally at least). Today, over five years after the game was first released to retail stores, Quake 4 is now available to purchase and download via the Impulse download service.

First released back in the fall of 2005, this fourth installment of the Quake series was a collaboration between id and Raven Software and basically continued the storyline from 1997's Quake II. It was also one of the few games that used id's Doom 3 graphics engine. Originally published by Activision Quake 4 is now owned by id's current owner Bethesda Softworks. You can get the game now for $19.99.