A Netherlands based design company had 3 quiz projects for mobile apps. The quizzes were broadly similar, in that they presented questions on various topics and each user was placed on a leader board based on the answers.
We wrote a gaming engine where questions could be configured with appropriate scores. The server also calculated medals, the score board and allowed reporting on results. All data was exposed via a JSON API to the app.
These projects were intended to be short-lived, as they were part of a advertising campaign for various European companies.