The Zac Brown Band used Twilio to create a unique fan engagement experience where fans could leave messages for the band by calling a dedicated phone number and recording their thoughts, memories or favorite songs. The prototype app was built using Python and ran on approximately 60 lines of code. The goal was to greet the caller, allow them to record a message, tell Twilio when they were done, and bid adieu, with a maximum message length of 30 seconds to ensure efficient use of time. The app utilized Flask for routing and Twilio's TwiML framework for handling voice calls and gathering user input.