For a limited time, DICE's Battlefield 3 is free to download and play on Origin through EA's "On the House" program. Essentially, this program, which aims to provide "a great gaming experience and a way to discover awesome new games," makes it so you can download full games, expansions, and more at absolutely no cost. And once you claim the game, it's yours to keep forever.
This isn't some trial either, this is the full retail version of Battlefield 3. Sure, it may be a few years old. And yes, we have Battlefield: Hardline to look forward to. But for someone possibly new to the Battlefield series, this is a great place for you to start. Admittedly, I haven't played BF3 in quite a while, so I'm a bit unfamiliar with the game's population at this point, but I'm willing to bet that this offer should up the numbers a bit. Hey, it's free, so no complaining here.
Battlefield 3 will be free to download until June 3, but EA urges you to act fast because On the House specials can appear and disappear at any time. On a sidenote, you also have until June 16 to download Plants vs. Zombies Game of the Year Edition for free.