Just to show how awesome they are, CD Projekt is marking the start of the summer with a one-of-a-kind promotion: the Battle of the Games, by which customers will vote on which games they'd like to see discounted over the next few weeks.

Every day from tomorrow (June 19) to July 5, two games will be up for a discount, and one will emerge victorious. You can head to GOG's Battle of the Games page to vote. Each round of voting begins at 9am EST, and after 24 hours, the winner will be discounted by 60 percent and the loser will be discounted by 40 percent for the subsequent 24 hours.

So yes, it's a win-win.

Tomorrow's offerings will be Myst: Masterpiece Edition and The 7th Guest, two classic PC adventure games, and you can vote on them now. And they promise to offer games like Psychonauts, The Witcher, and Broken Sword: Director's Cut during the course of the promotion.

To celebrate, two other classic PC games, Worlds of Ultima: The Savage Empire and Ultima: Worlds of Adventure 2: Martian Dreams are now free, forever, from GOG. So go download them.

Excited to start voting? Tell us in the comments or on Twitter.