Origin's On the House program now offers Plants vs. Zombies Game of the Year Edition as a free download, a 100% discount off its normal $4.99 price tag (thanks Tech ARP). The action/strategy is available for Windows and OS X, and requires an Origin account to redeem. Here's a refresher on the game:

What do you do when there's a zombie on your lawn? If you answered "start planting flowers to defeat it," then you've likely heard of Plants vs. Zombies. Armed with dozens of zombie-zapping plants, from the classic peashooter to the devious cherry bomb, you’ll need to think fast and plant faster to stop all types of zombies dead in their tracks. And just when you think you've got a handle on things, obstacles like a setting sun, creeping fog, and a swimming pool add to the challenge. With five game modes to dig into, the fun never dies!