Quizoid (Android, iOS) won't be winning any design awards for its Spartan looks, but the app is a challenging, no-nonsense single-player trivia game that strips out social extras and online components. Players try to get the highest scores they can by running through a gantlet of questions, while armed with three lifelines. Answer wrong, and the game is over. Quizoid features up to 7,000 questions in 17 categories, such as entertainment, mathematics and sports. In-app purchases add question packs, and can remove advertising. If you like your trivia games without any extra fluff, then give Quizoid a shot.