Although Humble Bundle, the site that lets you name your price for a plethora of games and e-books, has been around for years, today marks the one year anniversary of the Humble Store. For those who aren't aware, the Humble Store has many more games available than a typical bundle, but you can still select where the money goes to.
To celebrate this achievement, the company is giving a free copy of Metro 2033 to anyone who is interested. Simply go to the Humble Bundle site, enter your email address, and you'll be provided with a Steam key to download the game. That's all there is to it. The game is also pretty highly regarded: While not the best game of all-time, it does have a Metacritic score of 81, and the average user score is 8.2, so it's a quality title that's being offered.
If you want to grab a copy of Metro 2033 for yourself, be sure to sign up at the Humble Bundle site before 10am PT on Saturday. In addition, you must redeem your Steam key by November 21st, but once you redeem it, the game is yours forever.
Source: Humble Bundle