Keep alert when using the app Trailerpop, which blasts its users with quiz questions about cinema hits while the preview runs in the background, with loud music, and other clips. Questions might focus on other projects by the stars. The quicker one answers, the more points are gathered. There are also social network-like functions, with users allowed to create lists of their favourite films or to post their quiz results and compare them with friends'.
Users have to provide their name and email address when they start the app the first time. Beyond that, there are no fees for the app, available for both iOS and Android.
Since the videos are downloaded from online, it's best to use Trailerpop where one can access a wi-fi signal, otherwise the data flow can quickly exhaust a user's mobile download quotas.