There have been a number of opportunities to pick up some free PC games recently, and that's again the case right now. Steam and the Humble Store are each giving away a freebie right now, one of which is particularly excellent.
On the Humble Store, you can claim a free copy of Company of Heroes 2. Relic's World War II strategy game is now more than four years old, but it remains one of the genre's best. Although it did not expand on its predecessor in the way many hoped, it's nonetheless a solid game. Even all these years later, it remains extremely satisfying to dispatch foes by destroying the ice underneath them, causing them to sink. You can grab it here until 10 AM PT / 1 PM ET on Saturday, December 16. As is often the case with Humble games, this will get you a key to redeem on Steam.
You have less time to grab the other new freebie. Steam itself is giving away Homefront, the first-person shooter that images a version of the United States that's been occupied by North Korea. It's possible that you claimed a free version of this recently, as Humble gave it away just last week. Steam's offer runs for only one day, expiring at 10 AM PT / 1 PM ET on Friday, December 15. Grab it here.
While both of these offers are new to their respective stores, they aren't your only chance to claim a game completely for free. Following a promotion during the first half of the month, Ubisoft is now giving away Assassin's Creed IV: Black Flag for a limited time.