I recently discovered Quingo, a trivia game that offers a bunch of twists. Of course you have to answer trivia questions, but there are also objectives to meet. Each question has five correct answers, and you have to identify them quickly, out of a pool of as many as 25 potential answers. There is also a time element as well as "power ups" or "cheats" that you can earn to build your score.
Building your score is important, not just for bragging rights, but because the more you score, the more real world benefits you can earn for a number of charities. For example, I chose a charity that builds water wells for the needy. The more you play, the more the app developers, Game It Forward, donate to these causes!
The game itself is free, and with 500 questions it provides hours of entertainment. You can select from assorted in-app purchases for a variety of bonuses, including unlocking answers to questions you missed. So it's educational as well as fun. And it helps an assortment of worthy causes, which is a great idea.