Abstract: Reward system and related methods (100) used to compensate people for time spent participating in activities, in particular, time spent in activities (130) that people generally do not enjoy such as standing in line, providing answers to survey questions, and viewing and/or listening to advertisements. Such a reward system (100) may advantageously use a portable user interface device (300) adapted to allow a holder of the device (300) to interact with the reward system. Such a device may be adapted to allow a holder of the device to interact with multiple reward systems. Data relating to activity participation may be stored internally (320) in such a device (300), and/or may be temporarily stored in such a device and later be transmitted by the device to another device.