Application for testing general knowledge: This one is interesting. First activity shows catregories from which user wants to test his knowledge. When he clicks on one button, a dialog box shows subcategories. Every subcategory has four questions. After the user selects a subcategory, the next activity generates one of four question randomly. When questions are shown on screen, the clock starts ticking. Users have twenty seconds to answer one question. The user is scored depending on how many questions are answered correctly.