Honestly, I spent all day yesterday playing Pocket Frogs, so go try that if you haven't yet. But since we covered that one earlier this week, I'll tell you about Unearthed. To be honest, I don't exactly know how it all works. The app is complicated, and getting it to do what you want it to do is half the fun. It's designed to be like a government security app, except there's no five-inch thick manual binder to go along with it. The idea is that the app turns your iPhone into an "anomaly scanner," and with augmented reality, you're tasked with scanning various alien beings in the world around you. It's a little hard to explain, but once you play around with it, it's pretty trippy. You use the iPhone's camera (3GS or better required) to look around the actual space you're in, and aliens of various kinds appear on the screen as if they were actually there. Scan them in, and you earn points towards leaderboards and get recognized with bonuses and upgrades.
Unfortunately, as a game, Unearthed leaves something to be desired. It's a little clumsy, and as I said, it's not entirely clear what is happening, even when you figure out what all of the little buttons and lights do. A tutorial mode would be quite helpful, if the idea wasn't to engage the conspiracy theorist side of your mind.
But as an experience, Unearthed is definitely worth checking out. Fortunately, it's a free app that's supported by some in-game purchases for access to the highest levels. If nothing else, give it a download and see for yourself just how freaky augmented reality games can be.