One of the most popular social mobile games to play with friends and family over the last year is HQ Trivia. Mainly because they have REAL prizes and REAL money you can win each and every week.
I have friends that get the entire family together every single week to compete in HQ Trivia, and they never miss it. It's a weekly event. There's a real person, a live host, that emerges on your phone or tablet screen to ask the questions. Then, you'll battle against your friends, family, neighbors, strangers and the entire internet to try and win. If you do, you can earn money.
And yes, people win thousands of real dollars on HQ Trivia. Cold hard cash. It's pretty crazy, and they even have celebrity guests come on pretty often, too.