Qrank is the kind of game that I'm pretty sure we'll be seeing more of in the near future; it's a social quiz game that is fully powered by a connection to Facebook, Twitter, and its own in-game friend service. It's a free download off the App Store, and once you create an account (and connect it to any social services that you'd like), you get 20 brand new questions every day to try and answer for as many points as possible.
Something like this is complicated and painful if not done right, but Qrank (or QRANK, if you want to shout about it) has it just about dead-on. The login process is kind of a pain, but once things are set up, the quizzes move fast, and the questions are an interesting mix of history, pop culture, and general knowledge. The constant updates are a huge bonus as well; with a lot of quiz games, questions tend to repeat themselves, but the flow of new information means that there are new questions to answer every day.
I'm not 100% sure of the business model; there are ads, and I had a few questions that seemed branded (they made explicit mention of actual products). That leads me to believe that there are probably a few ways that Ricochet Labs is making money from players, and not all of them are completely clear. That may not bother you, though. If you've got a few friends to match scores with every day, Qrank seems like a fun, daily diversion into trivialand. Technology is making social, quickly updated games like this one much easier, and I think we'll end up seeing quite a few more of these in the future.