Green Man Gaming is offering a few free PC games this weekend. Starting at 7am Eastern every day from this Friday through Monday, a different game will be free for 24 hours. The first free game will be Zombies. on Friday, followed by Ninja Blade on Saturday, Unstoppable Gorg on Sunday and Superstars V8 Next Challenge on Monday. All told, the offer is worth about 40 bucks.
As you might expect, there is a catch – albeit a free catch. The first part is obvious: You'll need a Green Man Gaming account. You'll also have to sign up for Playfire, a service that tracks the games you play across multiple platforms (similar to Raptr). Finally, you'll have to link your GMG and Playfire accounts.
Once that's done, you'll be able to nab each game for free as they become available over the weekend.