Abstract: A person can use a computing device such as a computer, mobile device, or other such device to record the completion of a task. The task can include any task that is verifiable via the sensors associated with the mobile device. These sensors may be, for example, video, audio, a clock, a timer, still image, accelerometer based, gyro based, GPS location, locations according to triangulation, temperature, barometer, and the like. The task can then be sent to another person in the form of a challenge to do something better. The other person can then record a responsive task and send it to the challenger. The decision as to if the challenge has been met or beat can be decided by the challenger or someone else including a large voting audience. In some embodiments, a large number of people can respond to the challenge.