The Twilio API Mashup Developer Contest is a holiday challenge where developers are encouraged to build a digital Rube Goldberg machine using multiple APIs and Twilio capabilities. The contest aims to encourage creative use of Twilio's platform, with a focus on building something awesome every two weeks. The challenge requires participants to submit their project by January 1st, with bonus points for submission to the Twilio App Gallery and use of Twilio Client. Winners will receive a MacBook Air and a full-sized Christmas Story Leg Lamp, showcasing the creative potential of developers using Twilio's cloud communications platform.